Filtration sampling devices

Abstract

A filter support (2662) of a filtration assembly (2524) includes a rigid solid base (2664), which includes a first portion (2666), which defines filtrate -passage openings (1668) through the rigid solid base (2664) into a waste liquid receptacle (1656); and a second portion (2668), which defines a pres sure -release opening (2602) through the rigid solid base (2664) into the waste liquid receptacle (1656). A fluid-permeable layer (2604) is fixed to the rigid solid base (2664) covering the first portion (2666) without covering the second portion (2668). The fluid-permeable layer (2604) and the second portion (2668) of the rigid solid base (2664) together define a support surface (2659), on which a filter (60) is removably disposed. Pressurizing a liquid specimen sample in a tubular container (2030) at a pressure greater than a threshold pressure perforates a portion (2606) of the filter (60) covering the pressure-release opening (2602), and pushes a portion of the liquid specimen sample through the perforated portion (2606) and the pressure-release opening (2602), and into the waste liquid receptacle (1656). Other embodiments are also described.

Description

[0001] FILTRATION SAMPLING DEVICES

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present application claims priority from US Provisional Application 63 / 669,985, filed July 11, 2024, US Provisional Application 63 / 556,042, filed February 21, 2024, and US Provisional Application 63 / 621,875, filed January 17, 2024. All of the abovereferenced applications are assigned to the assignee of the present application and incorporated herein by reference.

[0004] FIELD OF THE APPLICATION

[0005] Applications of the present invention relate to sampling biological liquids.

[0006] BACKGROUND OF THE APPLICATION

[0007] Many techniques exist for testing for the presence of bacteria and viruses for aiding in disease diagnosis. For example, testing for the influenza virus includes molecular-based detection methods, viral culture methods, and immunoassay methods. Influenza virus testing includes the testing of nasal swabs, nasopharyngeal swabs, nasal aspirates, nasopharyngeal aspirates, nasal washes, nasopharyngeal washes, throat swabs, and a combination of samples.

[0008] PCT Publication WO 2018 / 158768 to Fruchter et al. describes inter alia a method for testing for presence of a particulate selected from the group consisting of: a microorganism, a fungus, a bacteria, a spore, a virus, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen. The method includes (a) collecting, in a tube, fluid that potentially contains the particulate, (b) using a plunger to push the fluid through a filter removably disposed at a distal portion of the tube or at a distal end of the plunger, and subsequently, (c) while the filter is inside the tube, ascertaining if any of the particulate was trapped by the filter by applying a particulate-presence-testing- facilitation solution to the filter.

[0009] PCT Publication WO 2020 / 049569 to Fruchter et al. describes inter alia a testing device for testing for the presence of particulate in a liquid. The testing device includes a liquid container for containing the liquid; a filter, disposed in or downstream of the liquid container; a liquid-pressure source, which is arranged to apply pressure to drive the liquid contained in the liquid container through the filter; and a filter chamber that is (a) disposed downstream of the liquid container, (b) shaped so as to define an inlet, and (c) in fluid communication with the filter.

[0010] PCT Publication WO 2022 / 149135 to Feldman et al. describes inter alia a sampling device for concentrating a liquid specimen sample, including a filtration assembly, which includes a tubular container and a plunger. The plunger includes a plunger head and a plunger rod that is shaped so as to define an internal plunger space having a plunger- space proximal opening through a proximal end of the plunger rod. The sampling device is configured such that a filter is removable from the tubular container via the plunger-space proximal opening while the plunger head is within the tubular container.

[0011] PCT Publication WO 2023 / 131948 to Levitz et al. describes inter alia a kit that includes an extraction tube or a transport tube; a filter; a liquid for bathing the filter within the tube; and a filter shaft. The filter shaft includes a distal portion that is coupled to a central portion of the filter. The filter shaft is configured to insert the filter into the tube for bathing the filter in the liquid. Other embodiments are also described.

[0012] PCT Publication WO 2024 / 013747 to Feldman et al. describes inter alia describes a filtration assembly that includes a tubular container shaped so as to define a proximal container opening for receiving a liquid specimen sample. A plunger includes a plunger head and a plunger rod, and is insertable into the tubular container via the proximal container opening. A filter support is shaped so as to define a support surface on which a filter is removably disposed, and a plurality of filtrate-passage openings through the filter support into a waste liquid receptacle. The filtration assembly is configured such that release of energy from a pre-loaded energy storage element, when the liquid specimen sample is contained in the tubular container and the filter is disposed on the support surface, pushes at least a portion of the liquid specimen sample through the filter and the filtratepassage openings and into the waste liquid receptacle. Other embodiments are also described.

[0013] US Patent Application Publication 2011 / 0318814 to Kshirsagar et al. describes inter alia a method for isolating microorganisms from a sample, the sample including sample matrix and microorganisms, the method including the steps of providing a receptacle, the receptacle configured to allow filtering of the sample and to reversibly contain the sample and a concentration agent; adding the sample to the receptacle, wherein a microorganismbound composition will be formed in the receptacle, the microorganism-bound composition including concentration agent-bound microorganisms and sample matrix; and filtering the microorganism-bound composition through a filter to collect the concentration agent-bound microorganisms on the filter. The filter has an average pore size that is greater than the average size of the microorganisms. Kits and systems are also described.

[0014] US Patent 5,077,012 to Guirguis describes an apparatus for collecting biological fluids and holding samples taken from a biological fluid for qualitative and quantitative testing. The apparatus comprises a tubular container open at both ends with a quantitative test storage unit removably secured to one of said tubular container ends. The quantitative test storage unit has an open end, a cytology membrane mounted in the storage unit and a retaining rib. A shuttle assembly is slidably mounted in the tubular container comprising a cylindrical hollow piston defining a chamber, a thumb cover covering one end of the piston and a fluid flow aperture formed in the piston and a qualitative sample container assembly removable secured to the piston. The qualitative sample container assembly comprises a clip on membrane assembly including a membrane containing immobilized antibodies and a filter housing mounted to the clip on membrane assembly. The filter housing is adapted to be seated in the quantitative test storage unit after being slidably transported along the tubular container by the piston.

[0015] US Patent 8,322,539 to Ellis et al. describes a filter vial for separating biological and chemical fluids having a cylindrical sidewall with an open top and a closed bottom. A protrusion extends upwards from the middle of the bottom to form an annular recess. A tubular plunger has an open bottom end to which is fastened an annular cup having an outer sidewall sized to fit into and seal against the vial's sidewall. An inner sidewall of the annular cup holds a filter over an opening in the bottom of the plunger and forms a shaped cavity leading to that filter. The annular cup on the plunger fits into the annular recess in the vial to force fluid from the vial through the filter and into the plunger.

[0016] US Patent Application Publication 2015 / 0076069 to Ellis et al. describes a filter vial and piston where the vial has a cylindrical wall with a closed bottom and open top and with the hollow, tubular piston therein. The piston has a position stop located and configured to abut a mating position stop on the vial to limit relative movement of the piston and vial. The position stops are located to stop the distal end of the piston away from the bottom of the vial a distance of about 10-30% the height of the vial. That a material to be dissolved in a liquid in the vial and to remove unwanted molecules from the liquid with the piston forcing the liquid through the filter but not squeezing the slurry of material so as to force it into the filter.

[0017] European Patent Application Publication EP 0 325 910 Al to Vcelka describes a sample filtration device of the type employing differential pressure. An outer container filled with a sample to be filtered slidably receives a hollow plunger having filter media disposed near one end and sealing means disposed in an annular groove about the periphery of the plunger. The annular groove of the plunger is formed by two components: an annular shoulder on a collector portion and the axial face of an annular ring formed in a retainer portion. The two portions are frictionally engaged to retain the filter in place and form the annular groove for the sealing means. This construction permits straight-pull molding of the component parts which eliminates mold mismatch flaws.

[0018] SUMMARY OF THE APPLICATION

[0019] Some applications of the present invention provide sampling devices for concentrating a liquid specimen sample. Some of the sampling devices comprise a filtration assembly, which comprises a tubular container for receiving the liquid specimen sample, a plunger, and a filter disposed in the tubular container. The filtration assembly is configured such that movement of a plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the filter is disposed in the tubular container, pushes at least a portion of the liquid specimen sample through the filter.

[0020] There is therefore provided, in accordance with an Inventive Concept 1 of the present invention, a sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises:

[0021] (i) a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample;

[0022] (ii) a plunger, which (a) comprises a plunger head and a plunger rod, which has a distal end portion to which the plunger head is coupled, and (b) is insertable into the tubular container via the proximal container opening, such that a lateral surface of the plunger head forms a fluid-tight movable seal with the inner wall of the tubular container;

[0023] (iii) a waste liquid receptacle;

[0024] (iv) a filter support, which comprises:

[0025] (a) a rigid solid base, which includes (1) a first portion, which is shaped so as to define a plurality of filtrate -passage openings through the rigid solid base into the waste liquid receptacle, and (2) a second portion, which is shaped so as to define a pres sure -release opening through the rigid solid base into the waste liquid receptacle; and

[0026] (b) a fluid-permeable layer, fixed to the rigid solid base covering the first portion without covering the second portion, wherein the fluid-permeable layer and the second portion of the rigid solid base together are shaped so as to define a support surface; and

[0027] (v) a filter, which is removably disposed on the support surface, wherein the filtration assembly is configured such that: pressurizing the liquid specimen sample in the tubular container at a first pressure less than a threshold pressure pushes a first portion of the liquid specimen sample (a) through the filter, (b) (1) partially through the fluid -permeable layer and the filtrate-passage openings and (2) partially through the pressure-release opening, and (c) into the waste liquid receptacle, and pressurizing the liquid specimen sample in the tubular container at a second pressure greater than the threshold pressure (i) perforates a portion of the filter covering the pressure -release opening and (ii) pushes a second portion of the liquid specimen sample through the perforated portion of the filter and the pressure -release opening, and into the waste liquid receptacle.

[0028] Inventive Concept 2. The sampling device according to Inventive Concept 1, wherein the fluid-permeable layer comprises a non-woven fabric, a woven fabric, or a mesh.

[0029] Inventive Concept 3. The sampling device according to Inventive Concept 1, wherein the fluid-permeable layer has a porosity greater than a porosity of the filter.

[0030] Inventive Concept 4. The sampling device according to Inventive Concept 1, wherein the pressure-release opening has a cross-sectional area greater than an average cross-sectional area of the filtrate-passage openings.

[0031] Inventive Concept 5. The sampling device according to Inventive Concept 1, wherein the first portion of the rigid solid base is shaped so as to define at least 5 filtrate-passage openings.

[0032] Inventive Concept 6. The sampling device according to Inventive Concept 5, wherein the first portion of the rigid solid base is shaped so as to define 5 - 1,000 filtrate-passage openings. Inventive Concept 7. The sampling device according to Inventive Concept 1, wherein respective portions of the support surface defined by the fluid-permeable layer and the second portion of the rigid solid base are flush with each other.

[0033] Inventive Concept 8. The sampling device according to Inventive Concept 1, wherein the rigid solid base is shaped so as to define no more than five pressure -release openings through the rigid solid base into the waste liquid receptacle.

[0034] Inventive Concept 9. The sampling device according to Inventive Concept 8, wherein the rigid solid base is shaped so as to define exactly one pressure-release opening through the rigid solid base into the waste liquid receptacle.

[0035] Inventive Concept 10. The sampling device according to any one of Inventive Concepts 1- 9, wherein the filtration assembly further comprises a dissolvable plug disposed in the pressure-release opening, wherein the dissolvable plug comprises a material that is configured to dissolve upon exposure to the liquid specimen sample, via the filter, for at least a threshold amount of time after commencement of exposure to the liquid specimen sample, and wherein, prior to dissolving of the material, the dissolvable plug prevents passage of the liquid specimen sample through the pressure -release opening even when the liquid specimen sample is pressured at the second pressure, and thereby prevents perforation of the portion of the filter covering the pressure-release opening.

[0036] Inventive Concept 11. The sampling device according to Inventive Concept 10, wherein the threshold amount of time is 30 - 300 seconds.

[0037] Inventive Concept 12. The sampling device according to Inventive Concept 10, wherein the pressure-release opening narrows at a downstream end portion thereof, in order to prevent the pressure applied to the dissolvable plug by the liquid specimen sample, via the filter, from ejecting the dissolvable plug from the downstream end portion prior to the dissolving of the dissolvable material.

[0038] Inventive Concept 13. The sampling device according to any one of Inventive Concepts 1- 9, wherein the plunger rod is shaped so as to define the waste liquid receptacle within the plunger rod, and wherein the plunger head comprises the filter support. Inventive Concept 14. The sampling device according to Inventive Concept 13, wherein the sampling device further comprises a container housing, and wherein the tubular container is disposed at least partially within the container housing, such that the tubular container is moveable with respect to the container housing and the plunger head.

[0039] Inventive Concept 15. The sampling device according to Inventive Concept 14, wherein the sampling device further includes a source of gas, which is configured to provide gas into a space by releasing or generating the gas, the space defined between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, and wherein the filtration assembly is configured such that providing the gas into the space increases pressure in the space, thereby proximally moving the tubular container with respect to the plunger head.

[0040] Inventive Concept 16. The sampling device according to any one of Inventive Concepts 1- 9, wherein an internal distal bottom surface of the tubular container comprises the filter support.

[0041] There is further provided, in accordance with an Inventive Concept 17 of the present invention, a method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device; inserting a plunger into the tubular container via the proximal container opening, such that a lateral surface of a plunger head of the plunger forms a fluid-tight movable seal with an inner wall of the tubular container, wherein the plunger further includes a plunger rod, which has a distal end portion to which the plunger head is coupled; and pressurizing the liquid specimen sample in the tubular container, wherein the filtration assembly further includes a filter support, which includes: a rigid solid base, which includes (i) a first portion, which is shaped as to define a plurality of filtrate-passage openings through the rigid solid base into a waste liquid receptacle of the filtration assembly, and (ii) a second portion, which is shaped so as to define a pressure-release opening through the rigid solid base into the waste liquid receptacle; and a fluid-permeable layer, fixed to the rigid solid base covering the first portion without covering the second portion, wherein the fluid-permeable layer and the second portion of the rigid solid base together are shaped so as to define a support surface, wherein a filter is removably disposed on the support surface, and wherein the filtration assembly is configured such that: pressurizing the liquid specimen sample in the tubular container at a first pressure less than a threshold pressure pushes a first portion of the liquid specimen sample (a) through the filter, (b) (1) partially through the fluid -permeable layer and the filtrate-passage openings and (2) partially through the pressure-release opening, and (c) into the waste liquid receptacle, and pressurizing the liquid specimen sample in the tubular container at a second pressure greater than the threshold pressure (i) perforates a portion of the filter covering the pressure -release opening and (ii) pushes a second portion of the liquid specimen sample through the perforated portion of the filter and the pressure -release opening, and into the waste liquid receptacle.

[0042] Inventive Concept 18. The method according to Inventive Concept 17, wherein the fluid- permeable layer includes a non-woven fabric, a woven fabric, or a mesh.

[0043] Inventive Concept 19. The method according to Inventive Concept 17, wherein the fluid- permeable layer has a porosity greater than a porosity of the filter.

[0044] Inventive Concept 20. The method according to Inventive Concept 17, wherein the pressure-release opening has a cross-sectional area greater than an average cross-sectional area of the filtrate-passage openings.

[0045] Inventive Concept 21. The method according to Inventive Concept 17, wherein the first portion of the rigid solid base is shaped so as to define at least 5 filtrate -passage openings.

[0046] Inventive Concept 22. The method according to Inventive Concept 21, wherein the first portion of the rigid solid base is shaped so as to define 5 -1,000 filtrate-passage openings.

[0047] Inventive Concept 23. The method according to Inventive Concept 17, wherein respective portions of the support surface defined by the fluid-permeable layer and the second portion of the rigid solid base are flush with each other. Inventive Concept 24. The method according to Inventive Concept 17, wherein the rigid solid base is shaped so as to define no more than five pressure-release openings through the rigid solid base into the waste liquid receptacle.

[0048] Inventive Concept 25. The method according to Inventive Concept 24, wherein the rigid solid base is shaped so as to define exactly one pressure-release opening through the rigid solid base into the waste liquid receptacle.

[0049] Inventive Concept 26. The method according to any one of Inventive Concepts 17-25, wherein the filtration assembly further includes a dissolvable plug disposed in the pressure-release opening, wherein the dissolvable plug includes a material that is configured to dissolve upon exposure to the liquid specimen sample, via the filter, for at least a threshold amount of time after commencement of exposure to the liquid specimen sample, and wherein, prior to dissolving of the material, the dissolvable plug prevents passage of the liquid specimen sample through the pressure -release opening even when the liquid specimen sample is pressured at the second pressure, and thereby prevents perforation of the portion of the filter covering the pressure-release opening.

[0050] Inventive Concept 27. The method according to Inventive Concept 26, wherein the threshold amount of time is 30 - 300 seconds.

[0051] Inventive Concept 28. The method according to Inventive Concept 26, wherein the pressure-release opening narrows at a downstream end portion thereof, in order to prevent the pressure applied to the dissolvable plug by the liquid specimen sample, via the filter, from ejecting the dissolvable plug from the downstream end portion prior to the dissolving of the dissolvable material.

[0052] Inventive Concept 29. The method according to any one of Inventive Concepts 17-25, wherein the plunger rod is shaped so as to define the waste liquid receptacle within the plunger rod, and wherein the plunger head includes the filter support.

[0053] Inventive Concept 30. The method according to Inventive Concept 29, wherein the sampling device further includes a container housing, wherein the tubular container is disposed at least partially within the container housing, such that the tubular container is moveable with respect to the container housing and the plunger head, and wherein pressurizing the liquid specimen sample in the tubular container comprises proximally moving the tubular container with respect to the plunger head.

[0054] Inventive Concept 31. The method according to Inventive Concept 30, wherein the sampling device further includes a source of gas, which is configured to provide gas into a space by releasing or generating the gas, the space defined between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, and wherein proximally moving the tubular container with respect to the plunger head comprises causing the source of gas to provide the gas into the space to as to increases pressure in the space.

[0055] Inventive Concept 32. The method according to any one of Inventive Concepts 17-25, wherein an internal distal bottom surface of the tubular container includes the filter support.

[0056] There is still further provided, in accordance with an Inventive Concept 33 of the present invention, a sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer comprising a main-filter-withdrawal shaft, which is directly or indirectly coupled to the main filter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the main-filter- withdrawal shaft out of the filtration assembly pulls the main filter from the filtration assembly, while leaving the prefilter within the filtration assembly.

[0057] Inventive Concept 34. The sampling device according to Inventive Concept 33, wherein the filtration assembly comprises a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate-passage openings through the prefilter support, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0058] Inventive Concept 35. The sampling device according to any one of Inventive Concepts 33- 34, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly comprises a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein the pressure source is configured, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0059] Inventive Concept 36. The sampling device according to Inventive Concept 33, wherein the sampling device further comprises a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0060] Inventive Concept 37. The sampling device according to Inventive Concept 36, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter is advanceable into the main- filter-collection receptacle via the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0061] Inventive Concept 38. The sampling device according to Inventive Concept 37, wherein the sampling device further comprises a shaft, and wherein the sampling device is configured such that that a distal portion of the shaft is axially movable through the receptacle opening so as to advance the main filter into the main-filter-collection receptacle via the receptacle opening.

[0062] Inventive Concept 39. The sampling device according to Inventive Concept 36, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly by distal movement of the main-filter-collection receptacle with respect to the tubular container.

[0063] Inventive Concept 40. The sampling device according to any one of Inventive Concepts 33- 39, wherein the pressure source comprises a plunger, which comprises a plunger head and a plunger rod, and which is insertable into the tubular container via the proximal container opening, and wherein the filtration assembly is configured such that movement of the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample through the prefilter and the main filter.

[0064] Inventive Concept 41. The sampling device according to Inventive Concept 40, wherein the plunger rod (1) has a distal end portion to which the plunger head is coupled, and (2) is shaped so as to define an internal plunger space having a plunger-space proximal opening through a proximal end of the plunger rod, wherein the plunger head is shaped so as to define a plunger-head opening through the plunger head and into the internal plunger space, wherein the main filter is removably disposed on a distal end of the plunger head, wherein the prefilter is fixed to the plunger head distal to the main filter, wherein the main-filter-withdrawal shaft is disposed passing through the internal plunger space, wherein insertion of the plunger into the tubular container via the proximal container opening inserts the main filter and the prefilter into the tubular container and forms a fluid- tight movable seal between a lateral surface of the plunger head and an inner wall of the tubular container, wherein the filtration assembly is configured such that the movement of the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the distal end of the plunger head in the tubular container, pushes at least a portion of the liquid specimen sample through the prefilter and the main filter, and wherein the sampling device is configured such that while the plunger head is within the tubular container: the proximal withdrawal of the main-filter-withdrawal shaft out of the internal plunger space pulls the main filter into the internal plunger space via the plunger-head opening and out of the internal plunger space via the plunger-space proximal opening, and removes the main-filter- withdrawal shaft and the main filter from the filtration assembly, while leaving the prefilter fixed to the plunger head.

[0065] Inventive Concept 42. The sampling device according to Inventive Concept 41, wherein the plunger head is shaped so as to define a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtratepassage openings through the prefilter support, wherein the prefilter support is disposed distal to the main filter, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0066] Inventive Concept 43. The sampling device according to any one of Inventive Concepts 41- 42, wherein the plunger rod is shaped so as to define therewithin a waste liquid receptacle, wherein the plunger head is shaped so as to define a main filter support, which is shaped so as to define (a) a main distal support surface, (b) a plurality of main filtratepassage openings through the main filter support into the waste liquid receptacle, and (c) the plunger-head opening, wherein the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head, and wherein the filtration assembly is configured such that when the liquid specimen sample is contained in the tubular container, the plunger head is within the tubular container, and the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head in the tubular container: the movement of the plunger head within the tubular container pushes the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0067] Inventive Concept 44. The sampling device according to Inventive Concept 41, wherein the sampling device further comprises a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0068] Inventive Concept 45. The sampling device according to Inventive Concept 44, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly while the plunger head is within the tubular container.

[0069] Inventive Concept 46. The sampling device according to Inventive Concept 44, wherein the main-filter-collection receptacle is removably disposed at least partially within the internal plunger space.

[0070] Inventive Concept 47. The sampling device according to Inventive Concept 46, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly while the plunger head is within the tubular container.

[0071] Inventive Concept 48. The sampling device according to Inventive Concept 46, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening and a shaft-passage hole at an end of the main-filter-collection receptacle opposite the receptacle opening, wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle via the plunger-head opening and the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly, wherein the main-filter-withdrawal shaft (a) is disposed partially within the main- filter-collection receptacle within the internal plunger space, (b) includes a proximal portion that is slidably disposed passing through the shaft -passage hole, and (c) includes the distal portion that passes through the receptacle opening and is directly or indirectly coupled to the main filter, and wherein the sampling device is configured such that proximal withdrawal of the main-filter- withdrawal shaft, while the plunger head is within the tubular container, pulls the main filter into the main-filter-collection receptacle via the plunger-head opening and the receptacle opening.

[0072] Inventive Concept 49. The sampling device according to Inventive Concept 48, wherein the sampling device is configured such that further proximal withdrawal of the main-filter- withdrawal shaft out of the internal plunger space, while the plunger head is within the tubular container, pulls the main-filter-collection receptacle out of the internal plunger space via the plunger-space proximal opening.

[0073] Inventive Concept 50. The sampling device according to Inventive Concept 48, further comprising a seal that inhibits fluid leakage between the proximal portion of the main-filter- withdrawal shaft and the shaft-passage hole.

[0074] Inventive Concept 51. The sampling device according to Inventive Concept 44, wherein the main-filter-collection receptacle is positioned proximal to the plunger head, and wherein the sampling device is configured such that the movement of the plunger head and the main-filter-collection receptacle within the tubular container advances the main filter into the filter-collection receptacle via the plunger-head opening.

[0075] Inventive Concept 52. The sampling device according to Inventive Concept 51, wherein the sampling device is configured such that the movement of the plunger head and the filtercollection receptacle within the tubular container advances the main filter into the filtercollection receptacle via the plunger-head opening while the main filter remains stationary with respect to a distal end of the tubular container.

[0076] Inventive Concept 53. The sampling device according to Inventive Concept 51, wherein the filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter is advanceable into the filter-collection receptacle via the receptacle opening while the filtercollection receptacle is disengageably coupled to the filtration assembly, and wherein the filter-collection receptacle is positioned proximal to the plunger head such that the receptacle opening is in fluid communication with the plunger-head opening.

[0077] Inventive Concept 54. The sampling device according to Inventive Concept 44, wherein the sampling device is configured such that the main filter is advanceable into the main-filter- collection receptacle while the plunger head is within the tubular container. Inventive Concept 55. The sampling device according to Inventive Concept 54, wherein the sampling device is configured such that the main filter is advanceable into the main-filter- collection receptacle while the plunger head is advanced as far as possible within the tubular container.

[0078] Inventive Concept 56. The sampling device according to Inventive Concept 33, wherein the pressure source comprises a source of gas, configured to provide gas into a space defined within the filtration assembly, and wherein the filtration assembly is configured such that providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample through the prefilter and the main filter.

[0079] Inventive Concept 57. A testing kit comprising the sampling device according to Inventive Concept 33, the testing kit further comprising a lateral flow immunoassay test strip, which is configured to detect a presence of a biological particulate trapped by the main filter.

[0080] Inventive Concept 58. The testing kit according to Inventive Concept 57, further comprising reagents for use with the lateral flow immunoassay test strip.

[0081] Inventive Concept 59. The testing kit according to Inventive Concept 58, further comprising an extraction tube, into which the main filter is insertable for bathing in the reagents.

[0082] Inventive Concept 60. The testing kit according to Inventive Concept 57, wherein the biological particulate is selected from the group consisting of: a virus, a bacterium, a microorganism, a fungus, a spore, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen.

[0083] Inventive Concept 61. The sampling device according to Inventive Concept 33, wherein the sampling device is configured to bunch up at least a portion of the main filter during removal of the main filter from the tubular container.

[0084] Inventive Concept 62. The sampling device according to Inventive Concept 61, wherein the sampling device is configured to bunch up the at least a portion of the main filter into a flower-like arrangement during the removal of the main filter from the tubular container.

[0085] There is additionally provided, in accordance with an Inventive Concept 63 of the present invention, a method for concentrating a liquid specimen sample, the method comprising: placing the liquid specimen sample in a tubular container of a filtration assembly of a sampling device; when the liquid specimen sample is contained in the tubular container and a main filter is in fluid communication with the liquid specimen sample via a prefilter disposed upstream of the main filter in fluid communication with the main filter, activating a pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter; and withdrawing a main-filter-withdrawal shaft of a withdrawer out of the filtration assembly, so as to pull the main filter from the filtration assembly, while leaving the prefilter within the filtration assembly, wherein the main-filter- withdrawal shaft is directly or indirectly coupled to the main filter.

[0086] Inventive Concept 64. The method according to Inventive Concept 63, wherein the filtration assembly includes a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support, and wherein activating the pressure source comprises activating the pressure source when the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0087] Inventive Concept 65. The method according to Inventive Concept 63, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly includes a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein activating the pressure source comprises activating the pressure source, when the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, so as to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0088] Inventive Concept 66. The method according to Inventive Concept 63, wherein the sampling device further includes a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the method further comprises advancing the main filter into the main-filter- collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0089] Inventive Concept 67. The method according to Inventive Concept 66, wherein the main- filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the method further comprising advancing the main filter into the main-filter-collection receptacle via the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0090] Inventive Concept 68. The method according to Inventive Concept 67, wherein the sampling device further includes a shaft, and wherein advancing the main filter into the main-filter-collection receptacle comprises axially moving a distal portion of the shaft through the receptacle opening.

[0091] Inventive Concept 69. The method according to Inventive Concept 66, wherein decoupling the main-filter-collection receptacle from the filtration assembly comprises distally moving the main-filter-collection receptacle with respect to the tubular container.

[0092] Inventive Concept 70. The method according to any one of Inventive Concepts 63-69, wherein the pressure source includes a plunger, which includes a plunger head and a plunger rod, and wherein activating the pressure source comprises: inserting the plunger head of the plunger into the tubular container via a proximal container opening of the tubular container; and moving the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, so as to push the at least a portion of the liquid specimen sample through the prefilter and the main filter.

[0093] Inventive Concept 71. The method according to Inventive Concept 70, wherein the plunger includes a plunger rod that (a) has a distal end portion to which the plunger head is coupled, and (b) is shaped so as to define an internal plunger space having a plunger-space proximal opening through a proximal end of the plunger rod, wherein the plunger head is shaped so as to define a plunger-head opening through the plunger head and into the internal plunger space, wherein the main filter is removably disposed on a distal end of the plunger head, wherein the prefilter is fixed to the plunger head distal to the main filter, wherein the main-filter-withdrawal shaft is disposed passing through the internal plunger space, wherein inserting the plunger head of the plunger into the tubular container via a proximal container opening inserts the main filter and the prefilter into the tubular container and forms a fluid-tight movable seal between a lateral surface of the plunger head and the inner wall of the tubular container, wherein moving the plunger head within the tubular container pushes at least a portion of the liquid specimen sample through the prefilter and the main filter, and wherein withdrawing the main-filter-withdrawal shaft comprises withdrawing the main-filter- withdrawal shaft out of the internal plunger space, so as to pull the main filter into the internal plunger space via the plunger-head opening and out of the internal plunger space via the plunger-space proximal opening, and remove the main-filter-withdrawal shaft and the main filter from the filtration assembly, while leaving the prefilter fixed to the plunger head.

[0094] Inventive Concept 72. The method according to Inventive Concept 71, wherein the plunger head is shaped so as to define a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtratepassage openings through the prefilter support, wherein the prefilter support is disposed distal to the main filter, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0095] Inventive Concept 73. The method according to any one of Inventive Concepts 71-72, wherein the plunger rod is shaped so as to define therewithin a waste liquid receptacle, wherein the plunger head is shaped so as to define a main filter support, which is shaped so as to define (a) a main distal support surface, (b) a plurality of main filtratepassage openings through the main filter support into the waste liquid receptacle, and (c) the plunger-head opening, wherein the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head, and wherein distally advancing the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container, the plunger head is within the tubular container, and the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head in the tubular container, pushes at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0096] Inventive Concept 74. The method according to Inventive Concept 71, wherein the sampling device further includes a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the method further comprises advancing the main filter into the main-filter- collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

[0097] Inventive Concept 75. The method according to Inventive Concept 74, wherein decoupling the main-filter-collection receptacle from the filtration assembly comprises decoupling the main-filter-collection receptacle from the filtration assembly while the plunger head is within the tubular container.

[0098] Inventive Concept 76. The method according to Inventive Concept 75, wherein decoupling the main-filter-collection receptacle from the filtration assembly comprises decoupling the main-filter-collection receptacle from the filtration assembly without proximally withdrawing the plunger head within the tubular container.

[0099] Inventive Concept 77. The method according to Inventive Concept 74, wherein distally advancing the plunger head within the tubular container comprises distally advancing the plunger head within the tubular container while the main-filter-collection receptacle is removably disposed at least partially within the internal plunger space.

[0100] Inventive Concept 78. The method according to Inventive Concept 77, wherein decoupling the main-filter-collection receptacle from the filtration assembly comprises decoupling the main-filter-collection receptacle from the filtration assembly while the plunger head is within the tubular container.

[0101] Inventive Concept 79. The method according to Inventive Concept 77, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening and a shaft-passage hole at an end of the main-filter-collection receptacle opposite the receptacle opening, wherein the main-filter-withdrawal shaft (a) is disposed partially within the main- filter-collection receptacle within the internal plunger space, (b) includes a proximal portion that is slidably disposed passing through the shaft -passage hole, and (c) includes the distal portion that passes through the receptacle opening and is directly or indirectly coupled to the main filter, and wherein advancing the main filter into the main-filter-collection receptacle comprises proximally withdrawing the main-filter- withdrawal shaft, while the plunger head is within the tubular container, so as to pull the main filter into the main-filter-collection receptacle via the plunger-head opening and the receptacle opening, while the main-filter- collection receptacle is disengageably coupled to the filtration assembly.

[0102] Inventive Concept 80. The method according to Inventive Concept 79, wherein decoupling the main-filter-collection receptacle from the filtration assembly comprises further proximally withdrawing the main-filter-withdrawal shaft out of the internal plunger space, while the plunger head is within the tubular container, so as to pull the main-filter-collection receptacle out of the internal plunger space via the plunger- space proximal opening.

[0103] Inventive Concept 81. The method according to Inventive Concept 74, wherein the main-filter-collection receptacle is positioned proximal to the plunger head, and wherein distally advancing the plunger head within the tubular container comprises distally advancing the plunger head and the main-filter-collection receptacle within the tubular container so as to advance the main filter into the main-filter-collection receptacle via the plunger-head opening.

[0104] Inventive Concept 82. The method according to Inventive Concept 81, wherein distally advancing the plunger head and the main-filter-collection receptacle within the tubular container advances the main filter into the main-filter-collection receptacle via the plungerhead opening while the main filter remains stationary with respect to a distal end of the tubular container.

[0105] Inventive Concept 83. The method according to Inventive Concept 81, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle via the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly, and wherein the main-filter-collection receptacle is positioned proximal to the plunger head such that the receptacle opening is in fluid communication with the plunger-head opening.

[0106] Inventive Concept 84. The method according to Inventive Concept 74, wherein advancing the filter into the main-filter-collection receptacle comprises advancing the main filter into the main-filter-collection receptacle while the plunger head is within the tubular container.

[0107] Inventive Concept 85. The method according to Inventive Concept 84, wherein advancing the main filter into the main-filter-collection receptacle comprises advancing the main filter into the main-filter-collection receptacle while the plunger head is advanced as far as possible within the tubular container.

[0108] Inventive Concept 86. The sampling device according to Inventive Concept 33, wherein the pressure source includes a source of gas, configured to provide gas into a space defined within the filtration assembly, and wherein activating the pressure source comprises causing the source of gas to provide the gas into the space, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to as to push the at least a portion of the liquid specimen sample through the prefilter and the main filter.

[0109] Inventive Concept 87. The method according to Inventive Concept 63, further comprising, after the main filter has been removed from the tubular container, detecting a presence of a biological particulate trapped by the main filter.

[0110] Inventive Concept 88. The method according to Inventive Concept 87, wherein detecting the presence of the biological particulate trapped by the main filter comprises using a lateral flow immunoassay test strip to detect the presence of the biological particulate trapped by the main filter.

[0111] Inventive Concept 89. The method according to Inventive Concept 88, wherein detecting the presence of the biological particulate trapped by the main filter comprises: inserting the main filter into an extraction tube and bathing the main filter in reagents; and thereafter using the lateral flow immunoassay test strip to detect the presence of the biological particulate trapped by the main filter.

[0112] Inventive Concept 90. The method according to Inventive Concept 87, wherein the biological particulate is selected from the group consisting of: a virus, a bacterium, a microorganism, a fungus, a spore, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen.

[0113] Inventive Concept 91. The method according to Inventive Concept 63, wherein the sampling device is configured to bunch up at least a portion of the main filter during removal of the main filter from the tubular container.

[0114] Inventive Concept 92. The method according to Inventive Concept 91, wherein the sampling device is configured to bunch up the at least a portion of the main filter into a flower-like arrangement during the removal of the main filter from the tubular container.

[0115] There is yet additionally provided, in accordance with an Inventive Concept 93 of the present invention, a sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly: pulls the main filter and the prefilter from the filtration assembly, and bunches up at least respective portions of the main filter and the prefilter, such that at least a part of the bunched-up portion of the prefilter is disposed outside the main filter.

[0116] Inventive Concept 94. The sampling device according to Inventive Concept 93, wherein the part of the bunched-up portion of the prefilter has a length, measured along the axis, of at least 3 mm. Inventive Concept 95. The sampling device according to Inventive Concept 94, wherein the length is at least 5 mm.

[0117] Inventive Concept 96. The sampling device according to Inventive Concept 93, wherein the part of the bunched-up portion of the prefilter has a length equal to at least 10% of a length of an entirety of the bunched-up portion of the prefilter, both lengths measured along the axis.

[0118] Inventive Concept 97. The sampling device according to Inventive Concept 96, wherein the length of the part of the bunched-up portion of the prefilter is less than 75% of the length of the entirety of the bunched-up portion of the prefilter.

[0119] Inventive Concept 98. The sampling device according to Inventive Concept 93, wherein the sampling device is configured such that withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly bunches up at least respective portions of the main filter and the prefilter into respective flower- like arrangements.

[0120] Inventive Concept 99. The sampling device according to Inventive Concept 98, wherein the sampling device is configured such that the withdrawal bunches up the at least respective portions of the main filter and the prefilter, such that an entirety of the bunched-up portion of the prefilter is disposed outside the main filter.

[0121] Inventive Concept 100. The sampling device according to Inventive Concept 93, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein the sampling device is configured such that, at least upon the withdrawal, a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis is at least 3 mm.

[0122] Inventive Concept 101. The sampling device according to Inventive Concept 100, wherein the distance is at least 5 mm.

[0123] Inventive Concept 102. The sampling device according to Inventive Concept 93, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein the sampling device is configured such that a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis increases during the withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly. Inventive Concept 103. The sampling device according to Inventive Concept 102, wherein the one or more filter- withdraw al shafts comprise: a first filter-withdrawal shaft that is coupled to the main-filter coupling portion of the main filter; and a second filter-withdrawal shaft that is coupled to the prefilter coupling portion of the prefilter, and wherein the first and the second filter-withdrawal shafts are configured to axially slide with respect to each other during the withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly, so as to increase the distance.

[0124] Inventive Concept 104. The sampling device according to Inventive Concept 103, wherein the first filter- withdrawal shaft is nested within at least an axial portion of the second filterwithdrawal shaft.

[0125] Inventive Concept 105. The sampling device according to Inventive Concept 93, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein the sampling device is configured such that a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis remains constant during the withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly.

[0126] Inventive Concept 106. The sampling device according to Inventive Concept 93, wherein an area of the prefilter equals 50% - 150% of an area of the main filter.

[0127] Inventive Concept 107. The sampling device according to Inventive Concept 106, wherein the area of the prefilter equals 90% - 110% of the area of the main filter.

[0128] Inventive Concept 108. The sampling device according to Inventive Concept 93, wherein the one or more filter-withdrawal shafts are coupled to respective central portions of the main filter and the prefilter.

[0129] Inventive Concept 109. The sampling device according to Inventive Concept 93, wherein the withdrawer comprises exactly one filter- withdrawal shaft.

[0130] Inventive Concept 110. The sampling device according to Inventive Concept 93, wherein the filtration assembly comprises a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate-passage openings through the prefilter support, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0131] Inventive Concept 111. The sampling device according to Inventive Concept 110, wherein the sampling device is configured such that the withdrawal of the one or more filterwithdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

[0132] Inventive Concept 112. The sampling device according to Inventive Concept 111, wherein the withdrawer comprises exactly one filter- withdrawal shaft.

[0133] Inventive Concept 113. The sampling device according to Inventive Concept 93, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly comprises a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein the pressure source is configured, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0134] Inventive Concept 114. The sampling device according to Inventive Concept 113, wherein the sampling device is configured such that the withdrawal of the one or more filterwithdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support within the filtration assembly.

[0135] Inventive Concept 115. The sampling device according to Inventive Concept 114, wherein the sampling device is configured such that the withdrawal of the one or more filterwithdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support and the prefilter support within the filtration assembly. Inventive Concept 116. The sampling device according to Inventive Concept 93, wherein the sampling device further comprises a flexible screen, which is disposed between the main filter and the prefilter.

[0136] Inventive Concept 117. The sampling device according to Inventive Concept 116, wherein the sampling device is configured such that the withdrawal of the one or more filterwithdrawal shafts out of the filtration assembly pulls the main filter, the flexible screen, and the prefilter from the filtration assembly.

[0137] Inventive Concept 118. The sampling device according to Inventive Concept 93, wherein the sampling device further comprises a filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the sampling device is configured such that the main filter and the prefilter are advanceable into the filter-collection receptacle while the filter-collection receptacle is disengageably coupled to the filtration assembly.

[0138] Inventive Concept 119. The sampling device according to Inventive Concept 118, wherein the filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter and the prefilter are advanceable into the filter-collection receptacle via the receptacle opening while the filter-collection receptacle is disengageably coupled to the filtration assembly.

[0139] Inventive Concept 120. The sampling device according to Inventive Concept 119, wherein the sampling device is configured such that that a distal portion of the one or more filterwithdrawal shafts is axially movable through the receptacle opening so as to advance the main filter and the prefilter into the filter-collection receptacle via the receptacle opening.

[0140] Inventive Concept 121. The sampling device according to any one of Inventive Concepts 93-120, wherein the pressure source comprises a plunger, which comprises a plunger head and a plunger rod, and which is insertable into the tubular container via the proximal container opening, and wherein the filtration assembly is configured such that movement of the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample downstream through the prefilter and the main filter. Inventive Concept 122. The sampling device according to Inventive Concept 121, wherein the plunger rod (1) has a distal end portion to which the plunger head is coupled, and (2) is shaped so as to define an internal plunger space having a plunger-space proximal opening through a proximal end of the plunger rod, wherein the plunger head is shaped so as to define a plunger-head opening through the plunger head and into the internal plunger space, wherein the main filter is removably disposed on a distal end of the plunger head, wherein the prefilter is removably coupled to the plunger head distal to the main filter, wherein the one or more filter-withdrawal shafts are disposed passing through the internal plunger space, wherein insertion of the plunger into the tubular container via the proximal container opening inserts the main filter and the prefilter into the tubular container and forms a fluid- tight movable seal between a lateral surface of the plunger head and the inner wall of the tubular container, wherein the filtration assembly is configured such that the movement of the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the distal end of the plunger head in the tubular container, pushes at least a portion of the liquid specimen sample through the prefilter and the main filter, and wherein the sampling device is configured such that while the plunger head is within the tubular container: the withdrawal of the one or more filter- withdrawal shafts out of the internal plunger space pulls the main filter and the prefilter into the internal plunger space via the plunger-head opening and out of the internal plunger space via the plungerspace proximal opening, and removes the one or more filter-withdrawal shafts, the main filter, and the prefilter from the filtration assembly.

[0141] Inventive Concept 123. The sampling device according to any one of Inventive Concepts 93-120, wherein the pressure source comprises a source of gas, configured to provide gas into a space defined within the filtration assembly, and wherein the filtration assembly is configured such that providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample downstream through the prefilter and the main filter.

[0142] There is also provided, in accordance with an Inventive Concept 124 of the present invention, a method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, wherein the filtration assembly further includes a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer including one or more filterwithdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source; when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, activating the pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter; and withdrawing the one or more filter-withdrawal shafts out of the filtration assembly so as to: pull the main filter and the prefilter from the filtration assembly, and bunch up at least respective portions of the main filter and the prefilter, such that at least a part of the bunched-up portion of the prefilter is disposed outside the main filter.

[0143] Inventive Concept 125. The method according to Inventive Concept 124, wherein the part of the bunched-up portion of the prefilter has a length, measured along the axis, of at least 3 mm.

[0144] Inventive Concept 126. The method according to Inventive Concept 125, wherein the length is at least 5 mm.

[0145] Inventive Concept 127. The method according to Inventive Concept 124, wherein the part of the bunched-up portion of the prefilter has a length equal to at least 10% of a length of an entirety of the bunched-up portion of the prefilter, both lengths measured along the axis.

[0146] Inventive Concept 128. The method according to Inventive Concept 127, wherein the length of the part of the bunched-up portion of the prefilter is less than 75% of the length of the entirety of the bunched-up portion of the prefilter. Inventive Concept 129. The method according to Inventive Concept 124, wherein withdrawing the one or more filter- withdraw al shafts out of the filtration assembly bunches up at least respective portions of the main filter and the prefilter into respective flower-like arrangements.

[0147] Inventive Concept 130. The method according to Inventive Concept 129, wherein withdrawing the one or more filter- withdraw al shafts out of the filtration assembly bunches up the at least respective portions of the main filter and the prefilter, such that an entirety of the bunched-up portion of the prefilter is disposed outside the main filter.

[0148] Inventive Concept 131. The method according to Inventive Concept 124, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein the sampling device is configured such that, at least upon the withdrawing of the one or more filter-withdrawal shafts out of the filtration assembly, a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis is at least 3 mm.

[0149] Inventive Concept 132. The method according to Inventive Concept 131, wherein the distance is at least 5 mm.

[0150] Inventive Concept 133. The method according to Inventive Concept 124, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly increases a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis.

[0151] Inventive Concept 134. The method according to Inventive Concept 133, wherein the one or more filter- withdraw al shafts include: a first filter-withdrawal shaft that is coupled to the main-filter coupling portion of the main filter; and a second filter-withdrawal shaft that is coupled to the prefilter coupling portion of the prefilter, and wherein the first and the second filter-withdrawal shafts are configured to axially slide with respect to each other during the withdrawing of the one or more filter- withdrawal shafts out of the filtration assembly, so as to increase the distance. Inventive Concept 135. The method according to Inventive Concept 134, wherein the first filter-withdrawal shaft is nested within at least an axial portion of the second filterwithdrawal shaft.

[0152] Inventive Concept 136. The method according to Inventive Concept 124, wherein the one or more filter-withdrawal shafts are coupled to a main-filter coupling portion of the main filter and a prefilter coupling portion of the prefilter, and wherein the sampling device is configured such that a distance between a first location of the main-filter coupling portion along the axis and a second location of the prefilter coupling portion along the axis remains constant during the withdrawing of the one or more filter-withdrawal shafts out of the filtration assembly.

[0153] Inventive Concept 137. The method according to Inventive Concept 124, wherein an area of the prefilter equals 50% - 150% of an area of the main filter.

[0154] Inventive Concept 138. The method according to Inventive Concept 137, wherein the area of the prefilter equals 90% - 110% of the area of the main filter.

[0155] Inventive Concept 139. The method according to Inventive Concept 124, wherein the one or more filter- withdrawal shafts are coupled to respective central portions of the main filter and the prefilter.

[0156] Inventive Concept 140. The method according to Inventive Concept 124, wherein the withdrawer includes exactly one filter- withdraw al shaft.

[0157] Inventive Concept 141. The method according to Inventive Concept 124, wherein the filtration assembly includes a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

[0158] Inventive Concept 142. The method according to Inventive Concept 141, wherein the sampling device is configured such that the withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

[0159] Inventive Concept 143. The method according to Inventive Concept 142, wherein the withdrawer includes exactly one filter- withdraw al shaft. Inventive Concept 144. The method according to Inventive Concept 124, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly includes a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein activating the pressure source comprises activating the pressure source, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate -pas sage openings and into the waste liquid receptacle.

[0160] Inventive Concept 145. The method according to Inventive Concept 144, wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support within the filtration assembly.

[0161] Inventive Concept 146. The method according to Inventive Concept 145, wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support and the prefilter support within the filtration assembly.

[0162] Inventive Concept 147. The method according to Inventive Concept 124, wherein the sampling device further includes a flexible screen, which is disposed between the main filter and the prefilter.

[0163] Inventive Concept 148. The method according to Inventive Concept 147, wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter, the flexible screen, and the prefilter from the filtration assembly.

[0164] Inventive Concept 149. The method according to Inventive Concept 124, wherein the sampling device further includes a filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the method comprises advancing the main filter and the prefilter into the filter-collection receptacle while the filter-collection receptacle is disengageably coupled to the filtration assembly.

[0165] Inventive Concept 150. The method according to Inventive Concept 149, wherein advancing comprises advancing the main filter and the prefilter into the filter-collection receptacle via a receptacle opening defined by the filter-collection receptacle, while the filter-collection receptacle is disengageably coupled to the filtration assembly.

[0166] Inventive Concept 151. The method according to Inventive Concept 150, wherein advancing the main filter and the prefilter into the filter-collection receptacle via the receptacle opening comprises axially moving a distal portion of the one or more filterwithdrawal shafts through the receptacle opening.

[0167] Inventive Concept 152. The method according to any one of Inventive Concepts 124-151, wherein activating the pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter comprises: inserting a plunger of the pressure source into the tubular container via the proximal container opening, the plunger including a plunger head and a plunger rod; and moving the plunger head within the tubular container.

[0168] Inventive Concept 153. The method according to Inventive Concept 152, wherein the plunger rod (1) has a distal end portion to which the plunger head is coupled, and (2) is shaped so as to define an internal plunger space having a plunger-space proximal opening through a proximal end of the plunger rod, wherein the plunger head is shaped so as to define a plunger-head opening through the plunger head and into the internal plunger space, wherein the main filter is removably disposed on a distal end of the plunger head, wherein the prefilter is removably coupled to the plunger head distal to the main filter, wherein the one or more filter-withdrawal shafts are disposed passing through the internal plunger space, wherein inserting the plunger into the tubular container via the proximal container opening inserts the main filter and the prefilter into the tubular container and forms a fluid- tight movable seal between a lateral surface of the plunger head and an inner wall of the tubular container, wherein moving the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the distal end of the plunger head in the tubular container, pushes at least a portion of the liquid specimen sample through the prefilter and the main filter, and wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly comprises withdrawing the one or more filter- withdrawal shafts out of the internal plunger space while the plunger head is within the tubular container, so as to: pull the main filter and the prefilter into the internal plunger space via the plunger-head opening and out of the internal plunger space via the plunger-space proximal opening, and remove the one or more filter- withdraw al shafts, the main filter, and the prefilter from the filtration assembly.

[0169] Inventive Concept 154. The method according to any one of Inventive Concepts 124-151, wherein the pressure source includes a source of gas, configured to provide gas into a space defined within the filtration assembly, and wherein activating the pressure source comprises activating the source of gas to provide the gas into the space, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, so as to push the at least a portion of the liquid specimen sample downstream through the prefilter and the main filter.

[0170] There is further provided, in accordance with an Inventive Concept 155 of the present invention, a sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support; a prefilter, which is disposed on the prefilter distal support surface of the prefilter support, upstream of the main filter in fluid communication with the main filter via the plurality of prefilter filtrate -pas sage openings; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

[0171] Inventive Concept 156. The sampling device according to Inventive Concept 155, wherein the withdrawer comprises exactly one filter- withdrawal shaft.

[0172] Inventive Concept 157. The sampling device according to Inventive Concept 155, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly comprises a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein the pressure source is configured, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0173] Inventive Concept 158. The sampling device according to Inventive Concept 157, wherein the sampling device is configured such that the withdrawal of the one or more filterwithdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support within the filtration assembly.

[0174] There is still further provided, in accordance with an Inventive Concept 159 of the present invention, a method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, wherein the filtration assembly further includes a main filter; a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support; a prefilter, which is disposed on the prefilter distal support surface of the prefilter support, upstream of the main filter in fluid communication with the main filter via the plurality of prefilter filtrate -pas sage openings; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source; when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, activating the pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter; and withdrawing the one or more filter-withdrawal shafts out of the filtration assembly so as to pull the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

[0175] Inventive Concept 160. The method according to Inventive Concept 159, wherein the withdrawer includes exactly one filter- withdraw al shaft.

[0176] Inventive Concept 161. The method according to Inventive Concept 159, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly includes a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -passage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein activating the pressure source, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, pushes the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

[0177] Inventive Concept 162. The method according to Inventive Concept 161, wherein withdrawing the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the main filter support within the filtration assembly. There is additionally provided, in accordance with an Inventive Concept 163 of the present invention, a sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises:

[0178] (i) a filter;

[0179] (ii) a container housing, which (a) is shaped so as to define a container-housing pressure-release vent, and (b) comprises a lateral wall;

[0180] (iii) a tubular container, which: is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample, and is disposed at least partially within the container housing in a vent-isolation position, such that the tubular container is moveable with respect to the container housing and forms a tubular-container fluid-tight movable seal with an inner surface of the lateral wall of the container housing, such that proximal motion of the tubular container with respect to the container housing expands a space within the filtration assembly between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, the space fluidly isolated from the container-housing pressurerelease vent;

[0181] (iv) a plunger, which comprises: a plunger rod, which is shaped so as to define a waste liquid receptacle; and a plunger head, which (a) is coupled to a distal end portion of the plunger rod, and (b) and comprises a filter support, which is shaped so as to define (a) a support surface on which the filter is removably disposed, and (b) a plurality of filtrate-passage openings through the filter support into the waste liquid receptacle, wherein the plunger is insertable into the tubular container via the proximal container opening, such that a lateral surface of the plunger head forms a plungerhead fluid-tight movable seal with the inner wall of the tubular container; and

[0182] (v) a source of gas, configured to provide gas into the space, wherein the filtration assembly is configured such that the providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the filter is disposed on the support surface: while the space is fluidly isolated from the container-housing pressurerelease vent, increases the pressure in the space so as to proximally move the tubular container with respect to the plunger head during a plunger stroke, thereby pushing at least a portion of the liquid specimen sample through the filter and the filtratepassage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, brings the space into fluid communication with the container-housing pressure-release vent, thereby releasing at least a portion of the gas from the space via the container-housing pressure-release vent.

[0183] Inventive Concept 164. The sampling device according to Inventive Concept 163, wherein, when the tubular container is disposed at least partially within the container housing in the vent-isolation position, the tubular-container fluid-tight movable seal is disposed distal to the container-housing pressure-release vent, thereby fluidly isolating the space from the container-housing pressure-release vent, and wherein the filtration assembly is configured such that the providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the filter is disposed on the support surface: while the tubular-container fluid-tight movable seal is disposed distal to the container-housing pressure-release vent, increases the pressure in the space so as to proximally move the tubular container with respect to the plunger head during the plunger stroke, thereby pushing the at least a portion of the liquid specimen sample through the filter and the filtrate -passage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, disposes the tubular-container fluid- tight movable seal at least partially proximal to the container-housing pressurerelease vent, thereby bringing the space into fluid communication with the container-housing pressure-release vent and releasing the at least a portion of the gas from the space via the container-housing pressure-release vent.

[0184] Inventive Concept 165. The sampling device according to Inventive Concept 163, wherein the container housing is shaped so as to define the container-housing pressure-release vent through the lateral wall of the container housing.

[0185] Inventive Concept 166. The sampling device according to Inventive Concept 163, wherein the container-housing pressure -release vent is in fluid communication with the atmosphere outside the filtration assembly. Inventive Concept 167. The sampling device according to Inventive Concept 163, wherein the source of gas comprises one or more substances that generate the gas.

[0186] Inventive Concept 168. The sampling device according to Inventive Concept 163, wherein the source of gas comprises a compressed gas container containing the gas.

[0187] Inventive Concept 169. The sampling device according to Inventive Concept 163, wherein the source of gas is configured to provide the gas upon manual activation of the source of gas.

[0188] Inventive Concept 170. The sampling device according to Inventive Concept 163, wherein the filtration assembly is configured such that movement of the plunger head within the tubular container causes the source of gas to provide the gas.

[0189] Inventive Concept 171. The sampling device according to Inventive Concept 163, wherein the filtration assembly is shaped so as to define a gas-release regulation chamber, which is in fluid communication with the space only by one or more openings, and wherein the source of gas is disposed in fluid communication with the gas-release regulation chamber.

[0190] Inventive Concept 172. The sampling device according to any one of Inventive Concepts 163-171, wherein the release of the at least a portion of the gas via the container-housing pressure-release vent actuates a mechanical user indicator.

[0191] Inventive Concept 173. The sampling device according to Inventive Concept 172, wherein the mechanical user indicator is acoustic.

[0192] Inventive Concept 174. The sampling device according to Inventive Concept 173, wherein the mechanical user indicator comprises a whistle, and wherein passage of the released at least a portion of the gas through the whistle blows the whistle.

[0193] Inventive Concept 175. The sampling device according to Inventive Concept 172, wherein the mechanical user indicator is visual.

[0194] Inventive Concept 176. The sampling device according to Inventive Concept 175, wherein the mechanical user indicator comprises a flag.

[0195] Inventive Concept 177. The sampling device according to any one of Inventive Concepts 163-171, wherein the filtration assembly further comprises a pressure-responsive valve that is configured to limit a pressure within the space even while the space is fluidly isolated from the container-housing pressure-release vent.

[0196] Inventive Concept 178. The sampling device according to Inventive Concept 177, wherein the pressure-responsive valve is configured to limit the pressure in the space by blocking flow of the gas into the space responsively to the pressure in the space.

[0197] Inventive Concept 179. The sampling device according to Inventive Concept 177, wherein the pressure-responsive valve comprises a pressure relief valve, which is configured to release a portion of the gas from the space when the pressure within the space exceeds a threshold pressure even while the space is fluidly isolated from the container-housing pressure-release vent.

[0198] Inventive Concept 180. The sampling device according to Inventive Concept 179, wherein the pressure relief valve is located so as to release the portion of the gas from the space to the atmosphere outside the filtration assembly when the pressure within the space exceeds the threshold pressure.

[0199] There is yet additionally provided, in accordance with an Inventive Concept 181 of the present invention, a method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, while the tubular container is disposed at least partially within a container housing of the filtration assembly in a ventisolation position, such that the tubular container is moveable with respect to the container housing and forms a tubular-container fluid-tight movable seal with an inner surface of a lateral wall of the container housing, such that proximal motion of the tubular container with respect to the container housing expands a space within the filtration assembly between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, the space fluidly isolated from a container-housing pressure-release vent defined by the container housing; inserting a plunger head of a plunger of the filtration assembly into the tubular container via the proximal container opening of the tubular container, such that a lateral surface of the plunger head forms a plunger-head fluid-tight movable seal with an inner wall of the tubular container, wherein the plunger further includes a plunger rod, which (a) has a distal end portion to which the plunger head is coupled, and (b) is shaped so as to define a waste liquid receptacle within the plunger rod, wherein the plunger head includes a filter support, which is shaped so as to define (a) a support surface on which a filter is removably disposed, and (b) a plurality of filtrate -passage openings through the filter support into the waste liquid receptacle; and causing a source of gas of the filtration assembly to provide gas into the space, so as to: while the space is fluidly isolated from the container-housing pressurerelease vent, increase the pressure in the space so as to proximally move the tubular container with respect to the plunger head during a plunger stroke, thereby pushing at least a portion of the liquid specimen sample through the filter and the filtratepassage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, bring the space into fluid communication with the container-housing pressure-release vent, thereby releasing at least a portion of the gas from the space via the container-housing pressure-release vent.

[0200] Inventive Concept 182. The method according to Inventive Concept 181, wherein, when the tubular container is disposed at least partially within the container housing in the vent-isolation position, the tubular-container fluid-tight movable seal is disposed distal to the container-housing pressure-release vent, thereby fluidly isolating the space from the container-housing pressure-release vent, and wherein causing the source of gas to provide the gas into the space: while the tubular-container fluid-tight movable seal is disposed distal to the container-housing pressure-release vent, increases the pressure in the space so as to proximally move the tubular container with respect to the plunger head during the plunger stroke, thereby pushing the at least a portion of the liquid specimen sample through the filter and the filtrate -passage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, disposes the tubular-container fluid- tight movable seal at least partially proximal to the container-housing pressurerelease vent, thereby bringing the space into fluid communication with the container-housing pressure-release vent and releasing the at least a portion of the gas from the space via the container-housing pressure-release vent. Inventive Concept 183. The method according to Inventive Concept 181, wherein the container housing is shaped so as to define the container-housing pressure-release vent through the lateral wall of the container housing.

[0201] Inventive Concept 184. The method according to Inventive Concept 181, wherein the container-housing pressure-release vent is in fluid communication with the atmosphere outside the filtration assembly.

[0202] Inventive Concept 185. The method according to Inventive Concept 181, wherein the source of gas includes one or more substances that generate the gas.

[0203] Inventive Concept 186. The method according to Inventive Concept 181, wherein the source of gas includes a compressed gas container containing the gas.

[0204] Inventive Concept 187. The method according to Inventive Concept 181, wherein causing the source of gas to provide the gas comprises manually activating the source of gas.

[0205] Inventive Concept 188. The method according to Inventive Concept 181, wherein causing the source of gas to provide the gas comprises moving the plunger head within the tubular container.

[0206] Inventive Concept 189. The method according to Inventive Concept 181, wherein the filtration assembly is shaped so as to define a gas-release regulation chamber, which is in fluid communication with the space only by one or more openings, and wherein the source of gas is disposed in fluid communication with the gas-release regulation chamber.

[0207] Inventive Concept 190. The method according to any one of Inventive Concepts 181-189, wherein the release of the at least a portion of the gas via the container-housing pressurerelease vent actuates a mechanical user indicator.

[0208] Inventive Concept 191. The method according to Inventive Concept 190, wherein the mechanical user indicator is acoustic.

[0209] Inventive Concept 192. The method according to Inventive Concept 191, wherein the mechanical user indicator includes a whistle, and wherein passage of the released at least a portion of the gas through the whistle blows the whistle.

[0210] Inventive Concept 193. The method according to Inventive Concept 190, wherein the mechanical user indicator is visual. Inventive Concept 194. The method according to Inventive Concept 193, wherein the mechanical user indicator includes a flag.

[0211] Inventive Concept 195. The method according to any one of Inventive Concepts 181-189, wherein the filtration assembly further includes a pressure-responsive valve that is configured to limit a pressure within the space even while the space is fluidly isolated from the container-housing pressure-release vent.

[0212] Inventive Concept 196. The method according to Inventive Concept 195, wherein the pressure-responsive valve is configured to limit the pressure in the space by blocking flow of the gas into the space responsively to the pressure in the space.

[0213] Inventive Concept 197. The method according to Inventive Concept 195, wherein the pressure-responsive valve includes a pressure relief valve, which is configured to release a portion of the gas from the space when the pressure within the space exceeds a threshold pressure even while the space is fluidly isolated from the container-housing pressure -release vent.

[0214] Inventive Concept 198. The method according to Inventive Concept 197, wherein the pressure relief valve is located so as to release the portion of the gas from the space to the atmosphere outside the filtration assembly when the pressure within the space exceeds the threshold pressure.

[0215] Inventive Concept 199. The method according to any one of Inventive Concepts 181-198, further comprising detecting the presence of a biological particulate trapped by the filter.

[0216] The present invention will be more fully understood from the following detailed description of embodiments thereof, taken together with the drawings, in which:

[0217] BRIEF DESCRIPTION OF THE DRAWINGS

[0218] Figs. 1A-B are schematic illustrations of a sampling device for concentrating a liquid specimen sample, and a portion of the sampling device, respectively, in accordance with an application of the present invention;

[0219] Figs. 2A-D are schematic illustrations of the sampling device of Figs. 1A-B and a method of using the sampling device, in accordance with respective applications of the present invention;

[0220] Figs. 3A-I are schematic cross-sectional illustrations of the sampling device of Figs. 1A-B and the method of using the sampling device, in accordance with respective applications of the present invention;

[0221] Figs. 3J-K are schematic illustrations of another method of using the sampling device of Figs. 1A-B, in accordance with an application of the present invention;

[0222] Fig. 4 is an enlarged schematic illustration of a portion of the sampling device of Figs. 1A-B, in accordance with an application of the present invention;

[0223] Figs. 5A-E are schematic illustrations of another sampling device for concentrating a liquid specimen sample, and a portion of the sampling device, respectively, in accordance with an application of the present invention;

[0224] Fig. 6 is a schematic illustration of a sampling device comprising a filter support, in accordance with an application of the present invention;

[0225] Figs. 7A-C are schematic illustrations of respective portions of the filter support of Fig. 6, in accordance with an application of the present invention;

[0226] Figs. 8A-B are schematic illustrations of a portion of the filter support of Fig. 6 before and after perforation of the filter, respectively, in accordance with an application of the present invention;

[0227] Figs. 8C-D are schematic illustrations of another configuration of a portion of the filter support of Fig. 6 before and after perforation of the filter, respectively, in accordance with an application of the present invention; and

[0228] Figs. 9A-E are schematic illustrations of another sampling device and a method of using the sampling device, in accordance with an application of the present invention;

[0229] Figs. 10A and 10B are schematic isometric and cross-sectional illustrations of the sampling device of Figs. 9A-E, in accordance with an application of the present invention;

[0230] Figs. 10C-D are exploded schematic illustrations of a portion of the sampling device of Figs. 9A-E, from two different directions, in accordance with an application of the present invention;

[0231] Fig. 11 is a cross-sectional schematic illustration a portion of the sampling device of Figs. 9A-E, in accordance with an application of the present invention; Figs. 12A-D are schematic cross-sectional illustrations of another sampling device for concentrating a liquid specimen sample, and a method of the using sampling device, in accordance with an application of the present invention;

[0232] Figs. 13A-D are schematic cross-sectional illustrations of yet another sampling device for concentrating a liquid specimen sample, and a method of the using sampling device, in accordance with an application of the present invention;

[0233] Figs. 14A-F are schematic cross-sectional illustrations of still another sampling device for concentrating a liquid specimen sample, and a method of the using sampling device, in accordance with an application of the present invention;

[0234] Figs. 15A-B are schematic illustrations of respective filter assemblies, respectively, in accordance respective applications of the present invention;

[0235] Figs. 16A-C are schematic illustrations of still another sampling device and a method of using the sampling device, in accordance with respective applications of the present invention; and

[0236] Figs. 17A-B are schematic illustrations of still another sampling device and a method of using the sampling device, in accordance with respective applications of the present invention;

[0237] Figs. 18A-D are schematic cross-sectional illustration of the sampling device of Fig. 17A-B and the method of using the sampling device, in accordance with respective applications of the present invention;

[0238] Figs. 19A-C are schematic illustrations of yet another sampling device and a method of using the sampling device, in accordance with respective applications of the present invention;

[0239] Figs. 20A-C are schematic cross-sectional illustrations of the sampling device of Fig. 19A-C and the method of using the sampling device, in accordance with respective applications of the present invention; and

[0240] Figs. 21A-B are schematic cross-sectional illustrations of another sampling device and a method of using the sampling device, in accordance with respective applications of the present invention. DETAILED DESCRIPTION OF APPLICATIONS

[0241] Figs. 1A-B are schematic illustrations of a sampling device 1620 for concentrating a liquid specimen sample 22, and a portion of the sampling device, respectively, in accordance with an application of the present invention.

[0242] Reference is also made to Figs. 2A-D, which are schematic illustrations of sampling device 1620 and a method of using sampling device 1620, in accordance with respective applications of the present invention.

[0243] Reference is also made to Figs. 3A-I, which are schematic cross-sectional illustrations of sampling device 1620 and a method of using sampling device 1620, in accordance with respective applications of the present invention. Reference is also made to Figs. 3J-K, which are schematic illustrations of another method of using sampling device 1620, in accordance with an application of the present invention.

[0244] Reference is further made to Fig. 4, which is an enlarged schematic illustration of a portion of sampling device 1620 in the state shown in Figs. 2D and 3D, in accordance with an application of the present invention.

[0245] Sampling device 1620 comprises a filtration assembly 1624 and a filter-collection receptacle 1650. The features of sampling device 1620, including but not limited to filtercollection receptacle 1650, may be implemented in any of the other sampling devices described hereinbelow, mutatis mutandis. Similarly, sampling device 1620 may be implemented in combination with any of the features of the other sampling devices described hereinbelow, mutatis mutandis, including, by way of example and not limitation, the reversible filter-clamping techniques of sampling devices 1820 or 1920, described in PCT Publication WO 2023 / 131948 to Levitz et al., which is incorporated herein by reference, with reference to Figs 11A-13F and Figs. 14A-16E thereof, respectively.

[0246] Filtration assembly 1624 comprises a tubular container 1630, a plunger 1640 (labeled in Fig. 3A), and a filter 60.

[0247] Tubular container 1630 is shaped so as to define a proximal container opening 1632 (labeled in Fig. 2 A) for receiving liquid specimen sample 22, after or during collection of liquid specimen sample 22 from the subject. Tubular container 1630 is also shaped so as to define an inner wall 1634 (labeled in Fig. 3A). At least a portion of tubular container 1630, such as a distal portion, may define a syringe barrel. As labeled in Figs. 2A and 3A, plunger 1640 comprises a plunger head 1642 and a plunger rod 1682. Plunger 1640 is insertable into tubular container 1630 via proximal container opening 1632, such that a lateral surface 1646 of plunger head 1642 (labeled in Fig. 3A) forms a fluid-tight movable seal with inner wall 1634. To this end, lateral surface 1646 may comprise an elastomeric material, such as natural rubber, synthetic rubber, a thermoplastic elastomer, or a combination thereof. Optionally, filtration assembly 1624 further comprises a plunger support 1658, which is coupled to a proximal portion of plunger 1640. Plunger support 1658 may be configured to be coupled to tubular container 1630. A portion of plunger support 1658 may serve as a handle to enable easy manipulation of plunger 1640, including insertion of plunger 1640 into tubular container 1630. Optionally, a portion of plunger support 1658 surrounds plunger 1640.

[0248] For some of these applications, plunger rod 1682 is shaped so as to define an internal plunger space 1686 (labeled in Fig. 3D). For some of these applications, a proximal end of plunger rod 1682 is shaped so as to define a plunger-space proximal opening 1690 of internal plunger space 1686. Plunger head 1642 is shaped so as to define a plunger-head opening 1644 (labeled in Fig. 3C) through plunger head 1642 and into internal plunger space 1686.

[0249] Typically, filter-collection receptacle 1650 is removably disposed at least partially within internal plunger space 1686.

[0250] Typically, filter-collection receptacle 1650 is positioned proximal to plunger head 1642.

[0251] Reference is made to Figs. 2A and 3A. Optionally, proximal container opening 1632 is shaped as a funnel to facilitate receipt of liquid specimen sample 22 during collection of the liquid specimen sample. For example, liquid specimen sample 22 may be expressed (e.g., spit) from subject's mouth into tubular container 1630, or transferred to tubular container 1630 from a collection container. Optionally, the funnel shape of proximal container opening 1632 is similar to funnel-shaped proximal opening 36 shown in Fig. 1 of US Patent Application Publication 2019 / 0381498 to Fruchter et al., which is incorporated herein by reference. Tubular container 1630, as well as any of the other tubular elements described herein, may be cylindrical, as shown, or may alternatively have another, non-circular cross-sectional shape. Alternatively or additionally, tubular container 1630 may have different cross-sectional shapes along respective different longitudinal portions of the tubular container; optionally, one or more of the cross-sectional shapes is circular.

[0252] Typically, tubular container 1630 has an internal volume of at least 0.5 ml (e.g., at least 1 ml, such as at least 5 ml), no more than 500 ml (e.g., no more than 70 ml), and / or 0.5 ml (e.g., 1 ml or 5 ml) - 500 ml (e.g., 70 ml).

[0253] For some applications, tubular container 1630 does not comprise a Luer lock or any other type of needle-coupling mechanism.

[0254] As shown in Figs. 2D, 3C, and 3D, filter-collection receptacle 1650 is typically shaped so as to define a receptacle opening 1652.

[0255] For some applications, filter-collection receptacle 1650 has a volume of at least 1 ml, no more than 50 ml, and / or 1 - 50 ml, such as at least 2 ml, no more than 20 ml, and / or 2 - 20 ml, e.g., at least 3 ml (e.g., at least 5 ml), no more than 15 ml, and / or 3 (e.g., 5) - 15 ml. For some applications, filter-collection receptacle 1650 has a greatest internal diameter of no more than 35 mm, e.g., no more than 20 mm, such as no more than 15 mm or no more than 10 mm.

[0256] Filter-collection receptacle 1650 typically has a greatest outer diameter that is less than (e.g., less than 80%, such as less than 70%) an inner diameter of an axial portion of tubular container 1630 in which plunger head 1642 is distally advanceable.

[0257] Filter-collection receptacle 1650 typically is not shaped so as to define any pressurerelease openings and does not comprise any pres sure -release valves.

[0258] Reference is made to Figs. 3B-D. Typically, filtration assembly 1624 further comprises a waste liquid receptacle 1656 for receiving a filtrate 61. For some of these applications, plunger rod 1682 is shaped so as to define therewithin waste liquid receptacle 1656. Typically, waste liquid receptacle 1656 partially or entirely surrounds internal plunger space 1686, such as shown.

[0259] For some applications, plunger head 1642 is shaped so as to define (integral with other portions of plunger head 1642 or as a separate piece attached to other portions of plunger head 1642) a filter support 1662 (labeled in Fig. 3A), which is shaped so as to define: • a support surface 1659, which may be perpendicular to a central longitudinal axis of plunger head 1642 (as shown), or may be angled with respect to the central longitudinal axis (configuration not shown),

[0260] • a plurality of filtrate-passage openings 1668 through filter support 1662 into waste liquid receptacle 1656, and

[0261] • a central opening that defines plunger-head opening 1644 (labeled in Figs. 3C and 3D).

[0262] Filter 60 is (removably) disposed on support surface 1659, typically on an upstream side of support surface 1659 (which, in the configuration of sampling device 1620, is a distal side of support surface 1659).

[0263] Reference is made to Figs. 2A-B and 3A-B. Filtration assembly 1624 is configured such that movement (typically distal advancement) of plunger head 1642 within tubular container 1630, when liquid specimen sample 22 is contained in tubular container 1630 and filter 60 is disposed in tubular container 1630, pushes at least a portion of liquid specimen sample 22 through filter 60. Filter 60 is configured to concentrate at least a portion of liquid specimen sample 22 onto filter 60, while allowing filtrate 61 to pass through filter 60. Typically, distal advancement of plunger 1640 within tubular container 1630 applies pressure to drive (e.g., push) at least a portion of liquid specimen sample 22 contained in tubular container 1630 through filter 60, such as shown in the transitions between Figs. 2A and 2B and between Figs. 3 A and 3B.

[0264] Filtration assembly 1624 is configured such that movement of plunger head 1642 within tubular container 1630, when liquid specimen sample 22 is contained in tubular container 1630 and filter 60 is disposed in tubular container 1630, pushes at least a portion of liquid specimen sample 22 through filter 60 and filtrate-passage openings 1668 and into waste liquid receptacle 1656.

[0265] Optionally, waste liquid receptacle 1656 is shaped so as to define an opening through an external wall of waste liquid receptacle 1656 to release displaced air. For example, the opening may be located on a proximal portion of the external wall, typically above the highest level that filtrate 61 is expected to reach during ordinary use of the device. For some applications, waste liquid receptacle 1656 comprises an air filter (e.g., an N98 filter) that is disposed to filter air that passes out of waste liquid receptacle 1656 through the opening. Alternatively or additionally, for some applications, waste liquid receptacle 1656 comprises a one-way pres sure- sensitive valve disposed in the opening.

[0266] Filter 60 comprises synthetic or natural materials formed, for example, as a matrix, membrane, fabric, beads, or other configuration. For some applications, filter 60 comprises a mechanical filter, which is configured to mechanically filter particulate from liquid specimen sample 22 by size-based filtration. Optionally, filter 60 comprises a depth filter.

[0267] Alternatively or additionally, for some applications, filter 60 comprises fixed antibodies configured to capture the particulate (e.g., free viral particles) by affinity-based filtration.

[0268] For some applications, for example, when filter 60 is used for capturing free virus, virions, or viral particles by size -based filtration, filter 60 may have a pore size of 0.01 - 0.3 microns and / or a molecular weight cut off of 10 kDa - 500 kDa. For some applications, filter 60 has a pore size of 0.2 - 5.0 microns, such as 0.2 - 2.0 microns (e.g., 0.8 to 1.5 microns, such as 1.2 microns), for example, when filter 60 is used for capturing bacteria by size-based filtration.

[0269] For some applications, filter 60 comprises a polyethersulfone (PES) membrane filter.

[0270] Alternatively or additionally, for some applications, filter 60 has a nominal pore size of 30 microns - 1.5 mm, the nominal pore size representative of a minimum size of spherical particles necessary for the filter to retain 85% of the spherical particles when H2O containing the spherical particles is passed through the filter at 20 degrees C under pressure supplied by a 10 cm water column. For these applications, filter 60 may implement techniques described in US Provisional Application 63 / 117,294, filed November 23, 2020, which is assigned to the assignee of the present application and incorporated herein by reference, and / or in PCT Publication WO 2021 / 224925 to Levitz et al., which is incorporated herein by reference.

[0271] For example, the nominal pore size may be at least 40 microns, such as at least 60 microns, e.g., at least 100 microns, at least 120 microns, at least 150 microns, at least 200 microns, or at least 500 microns. Alternatively or additionally, for example, the nominal pore size may be less than 1 mm, such as less than 750 microns, less than 500 microns, or less than 250 microns. For some applications, filtration assembly 1624 comprises a plurality of filters, such as described with reference to Figs. 10A-B in PCT Publication WO 2022 / 149135 to Feldman et al., which is assigned to the assignee of the present application and incorporated herein by reference. Optionally, two or more of the plurality of filters touch one another, such as shown in Figs. 10A-B of the '024 publication, or are separated by one another by one or more thin spacers, e.g., having a thickness of at least 0.05 mm, no more than 1 mm, and / or 0.05 - 1 mm (configuration not shown). Alternatively or additionally, two or more of the plurality of filters are spaced apart from another, which case filtration assembly 1624 optionally comprises a corresponding number of filter supports 1662, some or all of which may have some or all of the characteristics of filter support 1662 (configuration not shown). Further alternatively or additionally, filtration assembly 1624 comprises one or more additional filters downstream of filter 60 (configuration not shown).

[0272] Reference is made to Figs. 2D and 3D. Sampling device 1620 is typically configured such that filter 60 is removable from tubular container 1630 via a plunger-space proximal opening 1690 while plunger head 1642 of plunger 1640 (and typically filter support 1662) remains within tubular container 1630 (filter 60 is also removable from tubular container 1630 via plunger-space proximal opening 1690 if plunger head 1642 has been removed from tubular container 1630). As mentioned above, plunger head 1642 is shaped so as to define plunger-head opening 1644 through plunger head 1642 and into internal plunger space 1686 of plunger 1640.

[0273] Sampling device 1620 is configured such that filter 60 is advanceable into (e.g., entirely into) filter-collection receptacle 1650 via receptacle opening 1652 while filtercollection receptacle 1650 is disengageably coupled to filtration assembly 1624, such as shown in Figs. 2C and 3C.

[0274] Reference is made to Figs. 2C and 3C. For some applications, sampling device 1620 is configured such that filter 60 is advanceable into filter-collection receptacle 1650 via receptacle opening 1652 while plunger head 1642 (and typically filter support 1662) remains within tubular container 1630, such as shown in Figs. 2C and 3C. For some of these applications, sampling device 1620 is configured such that filter 60 is advanceable into filter-collection receptacle 1650 via receptacle opening 1652 while plunger head 1642 is advanced as far as possible within tubular container 1630, such as shown in Figs. 2C and 3C. Alternatively or additionally, for some applications, sampling device 1620 is configured such that filter 60 is advanceable into filter-collection receptacle 1650 via receptacle opening 1652 without any proximal withdrawal of plunger head 1642 within tubular container 1630, such as shown in Figs. 2C and 3C.

[0275] Reference is made to Figs. 2D and 3D. For some applications, sampling device 1620 is configured such that filter-collection receptacle 1650 is decouplable from filtration assembly 1624 while plunger head 1642 remains within tubular container 1630, such as shown in Figs. 2D and 3D, typically, but not necessarily, via a proximal end of plunger 1640. For some of these applications, sampling device 1620 is configured such that filtercollection receptacle 1650 is decouplable from filtration assembly 1624 while plunger head 1642 is advanced as far as possible within tubular container 1630, such as shown in Figs. 2D and 3D. Alternatively or additionally, for some applications, sampling device 1620 is configured such that filter-collection receptacle 1650 is decouplable from filtration assembly 1624 without any proximal withdrawal of plunger head 1642 within tubular container 1630, also such as shown in Figs. 2D and 3D.

[0276] Filter-collection receptacle 1650 is disengageably coupled to filtration assembly 1624. Once filter-collection receptacle 1650 has been decoupled from filtration assembly 1624, a diagnostic test may be performed for the presence of particulate trapped by filter 60, which is now in filter-collection receptacle 1650. For some applications, such as for transporting filter-collection receptacle 1650 to a remote diagnostic laboratory, sampling device 1620 further comprises filter-collection receptacle cap, which is configured to seal receptacle opening 1652.

[0277] For some applications, filter-collection receptacle 1650 is disengageably coupled to plunger 1640. Such as described hereinbelow, once filter-collection receptacle 1650 has been removed from plunger 1640, a diagnostic test may be performed for the presence of particulate trapped by filter 60, which is now in filter-collection receptacle 1650. For some applications, such as for transporting filter-collection receptacle 1650 to a remote diagnostic laboratory, sampling device 1620 further comprises a filter-collection receptacle cap, which is configured to seal receptacle opening 1652.

[0278] Reference is still made to Figs. 1A-4. For some applications, such as shown in Figs. 3A-4, sampling device 1620 comprises a withdrawer 1692, which comprises a filterwithdrawal shaft 1672. Filter- withdraw al shaft 1672:

[0279] • is disposed partially within filter-collection receptacle 1650 within internal plunger space 1686, • includes a proximal portion 1687 that is slidably disposed passing through a shaftpassage hole 1609 through an end 1604 of filter-collection receptacle 1650 opposite receptacle opening 1652 (labeled in Fig. 4), and

[0280] • includes a distal portion 1608 (labeled in Fig. 4) that is coupled or couplable (directly or indirectly) to filter 60, typically via an end 1604 of filter-collection receptacle 1650 opposite a receptacle opening 1652.

[0281] Sampling device 1620 is configured such that proximal movement (e.g., withdrawal) of filter-withdrawal shaft 1672, while plunger head 1642 (and typically filter support 1662) remains within tubular container 1630, collects filter 60 in filter-collection receptacle 1650 by pulling filter 60 at least partially into (such as entirely into) filtercollection receptacle 1650 via plunger-head opening 1644 (which, as mentioned above, is defined by the central opening of filter support 1662) via receptacle opening 1652 (as shown in the transitions between Figs. 2B and 2C and between Figs. 3B and 3C). At least a portion of filter 60 is typically bunched up within filter-collection receptacle 1650, such as into a flower-like arrangement, from the filter's initial flat shape while disposed on filter support 1662.

[0282] Typically, sampling device 1620 is configured such that further proximal withdrawal of filter-withdrawal shaft 1672 out of internal plunger space 1686, while plunger head 1642 (and typically filter support 1662) remains within tubular container 1630, pulls filter-collection receptacle 1650 out of internal plunger space 1686 via plungerspace proximal opening 1690 (as shown in the transitions between Figs. 2C and 2D and between Figs. 3C and 3D). It is noted that filter- withdraw al shaft 1672 of sampling device 1620 is not an element of filtration assembly 1624, but instead is removable therefrom, as shown in Figs. 2D and 3D.

[0283] For some applications, distal portion 1608 of filter- withdraw al shaft 1672 is coupled to filter 60 before use of filter 60 (typically during manufacture), while for other applications, distal portion 1608 of filter-withdrawal shaft 1672 is couplable to filter 60 during use of filter 60, such as, by way of example and not limitation, described in above- mentioned PCT Publication WO 2023 / 131948 with reference to Figs. 25A-E and 26A-E thereof.

[0284] For some applications, sampling device 1620 comprises a distal plate 1671 (labeled in Fig. 3A), which is disposed in contact with a distal surface of filter 60, and is coupled (directly or indirectly) to filter-withdrawal shaft 1672 through end 1604 of filter-collection receptacle 1650. For example, distal plate 1671 may be circular, i.e., shaped as a disc, or any other shape. Distal plate 1671 may be flexible, e.g., comprise silicone, or may be rigid, e.g., comprise metal or a polymer.

[0285] For some applications, withdrawer 1692 further comprises a shaft handle 1605, which is coupled to a proximal portion of filter-withdrawal shaft 1672. Optionally, shaft handle 1605 is shaped as a wing nut.

[0286] For some applications, filtration assembly 1624 (e.g., plunger-space proximal opening 1690 and / or plunger support 1658) and withdrawer 1692 (either shaft handle 1605 or filter-withdrawal shaft 1672) are shaped so as to define corresponding screw threads 1623A and 1623B (e.g., female and male screw threads 1623A and 1623B) (labeled in Fig. 3D), respectively, which (a) removably couple filter-withdrawal shaft 1672 to plunger rod 1682, such as shown in Fig. 3B, while filter-withdrawal shaft 1672 is disposed passing through internal plunger space 1686, and (b) prevent the premature proximal withdrawal of filter-withdrawal shaft 1672 out of internal plunger space 1686. Sampling device 1620 is configured such that rotation of filter- withdraw al shaft 1672 and plunger- space proximal opening 1690 with respect to each other (a) causes at least an initial portion of the proximal withdrawal of filter-withdrawal shaft 1672 out of internal plunger space 1686, such as shown in the transition between Fig. 3B and Fig. 3C, and (b) decouples female and male screw threads 1623 A and 1623B from each other, thereby allowing the continuation of the proximal withdrawal of filter-withdrawal shaft 1672 out of internal plunger space 1686, such as shown in Figs. 3C-D. Alternatively, shaft handle 1605 may be shaped so as to define screw thread 1623B, such as described hereinbelow regarding shaft handle 1805 and withdrawer 1892, mutatis mutandis.

[0287] Optionally, in configurations in which plunger support 1658 and / or plunger 1640 and tubular container 1630 are threadingly coupled to each other, (a) the threading between plunger- space proximal opening 1690 and filter-withdrawal shaft 1672 or shaft handle 1603 and (b) the threading between plunger 1640 and tubular container 1630 have opposite handedness.

[0288] For other applications, filtration assembly 1624 and filter-withdrawal shaft 1672 are not threadingly coupled together, and plunger- space proximal opening 1690 and shaft handle 1605 are not threadingly coupled together. Reference is made to Figs. 2D, 3A-F, and 4. For some applications, sampling device 1620 further comprises a seal 1614 that inhibits fluid leakage between proximal portion 1687 of filter-withdrawal shaft 1672 and shaft-passage hole 1609.

[0289] Optionally, an inner portion of seal 1614 may snap into an external circumferential groove of proximal portion 1687 of filter-withdrawal shaft 1672 upon the proximal withdrawal of most or all of filter-withdrawal shaft 1672 from filter-collection receptacle 1650, such as shown in Fig. 4.

[0290] Reference is again made to Figs. 1A-4. As described hereinabove, filter-withdrawal shaft 1672 include distal portion 1608 that is directly or indirectly coupled to filter 60. Exemplary ways in which the distal portion of the filter-withdrawal shaft may be directly or indirectly coupled to filter 60 include, but are not limited to:

[0291] • the distal portion of filter-withdrawal shaft 1672 may be directly coupled to filter 60, such as shown in Fig. 4, e.g., by an adhesive and / or by distal plate 1671 (labeled in Fig. 3A, which may be fixed, e.g., pinned, to the distal end of the distal portion of filter-withdrawal shaft 1672; in these configurations, the distal portion of the filter-withdrawal shaft passes through the end of the filter-collection receptacle opposite the receptacle opening; and

[0292] • the distal portion of filter-withdrawal shaft 1672 may be indirectly coupled to the filter, such as shown in Fig. 4, e.g., by a rod 1679 (labeled in Fig. 4) that (a) is fixed to the distal end of the distal portion of filter-withdrawal shaft 1672 and (b) passes through the end of the filter-collection receptacle opposite the receptacle opening, and optionally further by an adhesive and / or by distal plate 1671 which may be integral with rod 1679 or fixed to rod 1679.

[0293] It will be appreciated by persons skilled in the art who have read the present application that the distal portions of filter-withdrawal shaft 1672 may be directly or indirectly coupled to the filter in additional ways, all of which are within the scope of the present invention.

[0294] Reference is now made to Figs. 3E-I. For some applications, the method optionally continues as shown in Figs. 3E-I. By way of example and not limitation, filter-collection receptacle 1650 is shown as being shorter in Figs. 3E-I than in Figs. 1A-3D. In actual use, the filter-collection receptacle has the same length throughout its use, i.e., the same length in Figs. 1A-3D as in Figs. 3E-I. If the filter-collection receptacle is shorter than shown in Figs. 1A-3D, the filter-collection receptacle occupies only a proximal portion of internal plunger space 1686.

[0295] As shown in Figs. 3E-F, filter-collection receptacle 1650 is inserted at least partially into an extraction tube 1718, and distally advanced within extraction tube 1718 until bunched-up filter 60 is positioned near a distal end 1751 of extraction tube 1718 opposite a proximal end opening 1721. Extraction tube 1718 is shaped so as to prevent filter-collection receptacle 1650 from reaching distal end 1751 of extraction tube 1718, such that filtercollection receptacle 1650 slides up a portion of filter-withdrawal shaft 1672 as bunched- up filter 60 is positioned near distal end 1751, thereby ejecting bunched-up filter 60 from receptacle opening 1652 of filter-collection receptacle 1650 and exposing bunched-up filter 60 to a liquid 1030, such as described hereinbelow, within the distal portion of extraction tube 1718.

[0296] This technique may aid with the insertion of bunched-up filter 60 into extraction tube 1718. Filter-collection receptacle 1650 is readily inserted into extraction tube 1718, thereby inserting bunched-up filter 60 into extraction tube 1718 while the bunched-up filter is initially within filter-collection receptacle 1650. Filter-collection receptacle 1650 also may serve to cover and / or shield bunched-up filter 60 when filter 60 is exposed to the environment, such as before insertion into extraction tube 1718 and / or after optional removal from extraction tube 1718, such as described hereinbelow with reference to Figs. 3J, or in above-mentioned PCT Publication WO 2023 / 131948 with reference to Figs. 32G and 34D thereof; in this sense, filter-collection receptacle 1650 may also function as a sleeve for covering and / or shielding bunched-up filter 60.

[0297] Optionally, as shown in Figs. 3E-H, extraction tube 1718 may comprise a screw-off distal tip cap 1749 that removably seals distal end 1751 of extraction tube 1718 opposite proximal end opening 1721. The liquid within extraction tube 1718 may be expelled (e.g., squeezed or dripped out) of extraction tube 1718, such as described hereinbelow with reference to Fig. 31, or in above-mentioned PCT Publication WO 2023 / 131948 with reference to Figs. 9C-D thereof.

[0298] For some applications, such as shown in Fig. 3G, while bunched-up filter 60 is exposed to liquid 1030 in extraction tube 1718, filter 60 is squeezed (e.g., by squeezing flexible extraction tube 1718) at least one time without expelling any of liquid 1030 from extraction tube 1718. Screw-off distal tip cap 1749, if provided, is then removed from extraction tube 1718, such as shown in Fig. 3H.

[0299] For some applications, extraction tube 1718 is oriented horizontally (rather than vertically) during all or a portion of the exposure of bunched-up filter 60 to liquid 1030 in extraction tube 1718. For example, filter 60 may be rotated in extraction tube 1718, optionally while only partially immersed in liquid 1030.

[0300] As shown in Fig. 31, liquid 1030 within extraction tube 1718 is expelled (e.g., squeezed or dripped out) from extraction tube 1718, such as onto a sample pad 1797 of a lateral flow test strip 1799, such as a lateral flow immunoassay test strip. Alternatively, lateral flow test strip 1799 may comprise another type of lateral flow test strip, such as a CRISPR / Cas9-based lateral flow assay. Optionally, liquid 1030 is expelled from extraction tube 1718 by squeezing extraction tube 1718 at least one time, so as to both squeeze a portion of liquid 1030 from filter 60 and expel the portion of the liquid from the extraction tube. In the technique illustrated in Fig. 31, liquid 1030 within extraction tube 1718 is expelled from extraction tube 1718 while filter 60 remains within extraction tube 1718.

[0301] The techniques of Fig. 3E, Fig. 3F, Fig. 3G, Fig. 3H, and / or Fig. 31 may optionally be implemented in combination with the techniques of any of the sampling devices described herein.

[0302] For some applications, filter-collection receptacle 1650 is flexible. Bunched-up filter 60 is exposed to liquid 1030 in extraction tube 1718, as described above. The bunched-up filter is then withdrawn from extraction tube 1718 and pulled at least partially into filter-collection receptacle 1650 via receptacle opening 1652, by proximally moving filter-withdrawal shaft 1672 with respect to filter-collection receptacle 1650. Thereafter, the bunched-up portion of filter 60 is squeezed by squeezing filter-collection receptacle 1650, while at least a portion of the bunched-up filter 60 is covered and / or shielded by filtercollection receptacle 1650, to squeeze a portion of liquid 1030 from filter 60 (configuration not shown).

[0303] Reference is made to Figs. 3J-K. The step illustrated in Fig. 3J may optionally be performed after the step illustrated in Fig. 3F or after the step illustrated in Fig. 3G (i.e., with or without squeezing filter 60 while it is in extraction tube 1718). After bunched-up filter 60 has been exposed to liquid 1030 in extraction tube 1718 (typically bathed in liquid 1030 for a certain amount of time), filter-withdrawal shaft 1672 is withdrawn from extraction tube 1718. This proximal movement of filter- withdraw al shaft 1672 with respect filter-collection receptacle 1650 pulls filter 60 at least partially into (such as entirely into) filter-collection receptacle 1650 via receptacle opening 1652.

[0304] For some applications, bunched-up filter 60 is removed from extraction tube 1718 while extraction tube 1718 is squeezed. For example, extraction tube 1718 may be squeezed before removing bunched-up filter 60, such as shown in Fig. 3G, and extraction tube 1718 may continue to be squeezed during removal of bunched-up filter 60 from extraction tube 1718.

[0305] For some applications, after removal of filter 60 from extraction tube 1718, liquid 1030 is tested for the presence of a target analyte released into liquid 1030 from particulate trapped by filter 60. For example, a lateral flow test strip, such as a lateral flow immunoassay test strip, optionally implemented as a dipstick 1757, may be inserted into liquid 1030 in extraction tube 1718, such as shown in Fig. 3K.

[0306] Alternatively, the step illustrated in Fig. 3J may be followed by the techniques of Figs. 32H-K, 34E-F, or 35A-D of above-mentioned PCT Publication WO 2023 / 131948.

[0307] The techniques of Fig. 3J and / or Fig. 3K may optionally be implemented in combination with the techniques of any of the sampling devices described herein.

[0308] Alternatively, such as described in above-mentioned PCT Publication WO 2023 / 131948 with reference to Figs. 32H-K or 34E-F thereof, after bunched-up filter 60 is exposed to liquid 1030 in extraction tube 1718 (typically bathed in liquid 1030 for a certain amount of time), filter-collection receptacle 1650 is removed from extraction tube 1718, and filter 60 is squeezed to partially release the portion of liquid 1030 from filter 60, such as onto sample pad 1797 of lateral flow test strip 1799, such as a lateral flow immunoassay test strip. Alternatively, filter 60 is squeezed by squeezing flexible filter-collection receptacle 1650 (configuration not shown).

[0309] Reference is again made to Fig. 3J. For some applications, after bunched-up filter 60 is bathed in liquid 1030 within extraction tube (and optionally squeezed within extraction tube 1718), a portion of liquid 1030 is discarded, such as by draining the portion of liquid 1030 from extraction tube 1718. For example, extraction tube 1718 may have the configuration described hereinabove with reference to Figs. 3E-H, and screw-off distal tip cap 1749 may be removed from extraction tube 1718, such as shown in Fig. 3H, in order to discard the portion of liquid 1030. For some applications, liquid specimen sample 22 is received from a subject's mouth. For some applications, liquid specimen sample 22 comprises gargled fluid, i.e., a gargle fluid that the subject has gargled in his or her mouth and spit out, perhaps along with some saliva. In the present application, including in the claims and Inventive Concepts, "gargled fluid" means "gargle fluid" that has been gargled by a subject. Typically, the gargle fluid includes water, carbonated water, saline (e.g., phosphate buffered saline), pelargonium sidoides extract, tannic acid, balloon flower platycodon grandiflorus, berberine sulfate, S -carboxymethylcysteine, curcumin, coloring, flavoring, a detergent (such as Polysorbate 20 (e.g., Tween® 20)), or any combination thereof. In some applications, the gargle fluid is carbonated. Alternatively or additionally, for some applications, a detergent, such as Polysorbate 20 (e.g., Tween® 20) is added to the gargled fluid after being gargled by the subject. Alternatively, liquid specimen sample 22 may comprise another type of biological fluid, such as blood (e.g., diluted blood), urine, stool (e.g., diluted stool), gastrointestinal (GI) fluid, or bronchoalveolar lavage fluid.

[0310] Alternatively, liquid specimen sample 22 comprises saliva not swabbed from the throat of a subject (i.e., the saliva was collected without swabbing the subject's throat). (The distinction between "swab" as a verb and as a noun is noted. A "swab" (as a noun) may be used to obtain saliva without "swabbing" (as a verb) the subject's throat. For example, the subject may suck on a swab, or a swab may be dipped in a container into which gargle fluid or saliva has been placed.) By contrast, in commonly -practiced techniques for testing for strep, the tonsils are swabbed. Further alternatively, liquid specimen sample 22 comprises liquid from a cultured medium containing a biological sample which had been incubated within tubular container 30 or incubated separately from the device and then added to tubular container 30.

[0311] Liquid specimen sample 22 (e.g., saliva) may be spit directly by the subject into tubular container 30 or transferred by a healthcare worker from another container into which the subject spit. Alternatively, in the case of saliva, the saliva may be collected from the subject's mouth by having the subject suck on a swab or other absorbent collecting element, such as flocked swabs or cotton rolls.

[0312] For some applications in which the method does not comprise swabbing the throat of the subject, liquid specimen sample 22 is collected by drawing liquid specimen sample 22 out of an oral cavity of the subject via an anterior opening of the oral cavity by contacting one or more portions of the oral cavity with an absorbent material, e.g., a flocked or cotton swab, or a sponge (e.g., at a tip of a collector shaft), without swabbing the oropharynx of the subject. (For example, an ORAcollect®-RNA Saliva Collection Device (DNA Genotek Inc., a subsidiary of OraSure Technologies, Inc. (Bethlehem, PA, USA)) may be used.) Optionally, the absorbent material is located on a tip of a collector shaft, and liquid specimen sample 22 is drawn out of the oral cavity via the anterior opening of the oral cavity using the absorbent material by inserting the tip of the collector shaft into the oral cavity. For some of these applications, liquid specimen sample 22 is drawn out of the oral cavity via the anterior opening of the oral cavity using the absorbent material by the subject sucking on the absorbent material. For example, the one or more portions of the oral cavity may include one or more of buccal mucosa, the tongue (e.g., under the tongue), the gums (e.g., the lower gums), and / or the palatal mucosa. For example, for swabbing the lower gums, absorbent material (e.g., at a tip of a collector shaft) may be rubbed back and forth along the lower gums several times. (The anterior opening of the oral cavity is the opening of the mouth between the lips, between outside the oral cavity and inside the oral cavity.)

[0313] Alternatively, liquid specimen sample 22 comprises an incubated culture medium containing a biological sample.

[0314] Reference is still made to Figs. 1A-4. In some applications of the present invention, a method for concentrating liquid specimen sample 22 is provided. The method comprises:

[0315] • placing liquid specimen sample 22 in tubular container 1630 of filtration assembly 1624, such as shown in Figs. 2A and 3A;

[0316] • inserting plunger head 1642 of plunger 1640 into tubular container 1630 via proximal container opening 1632 of tubular container 1630, such as shown in the transition between Figs. 2A and 2B and between Figs. 3A and 3B;

[0317] • distally advancing plunger head 1642 within tubular container 1630 to drive at least a portion of liquid specimen sample 22 through filter 60 disposed in tubular container 1630, such as shown in Figs. 2B and 3B (it is noted that in this configuration, filter 60 is not initially disposed in tubular container 1630 when liquid specimen sample 22 is placed in tubular container 1630, and is inserted into tubular container 1630 as plunger head 1642 is inserted into tubular container); and

[0318] • removing filter 60 from tubular container 1630 via plunger-space proximal opening 1690 while plunger head 1642 and filter support 1662 remain within tubular container 1630, as shown in Figs. 2C-D and 3C-D. For some applications, liquid specimen sample 22 may be acquired and / or may have any of the characteristics described hereinabove.

[0319] For some applications, the method further comprises sealing receptacle opening 1652 with a filter-collection receptacle cap after filter 60 has been advanced into filtercollection receptacle 1650.

[0320] For some applications, the method further comprises, after filter 60 has been removed from tubular container 1630, detecting the presence of a biological particulate trapped by filter 60. For example, the biological particulate may be selected from the group consisting of: a virus, a bacterium, a microorganism, a fungus, a spore, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen.

[0321] The particulate may, for example, be a virus (e.g., an Influenza virus, or a coronavirus, such as SARS-CoV-2), a bacterium (e.g., Streptococcus bacteria, such as Streptococcus pyogenes (Strep A), or a bacterium that causes a sexually transmitted infection (STI), such as gonorrhea and / or chlamydia ), a microorganism, an antigen, a human cell, a cellular biomarker, a hormone, a chemical mediator from cells (e.g., a mediator of inflammation), a pollen, mucous, saliva, sputum, a respiratory particle, droplets derived from the upper and lower airways, a nucleic acid including DNA and RNA, and a chemical originating from external vapors. When the particulate is a microorganism, the microorganism may be either a pathogenic microorganism or a non-pathogenic microorganism or both, for example, viruses, bacteria, protozoa, and fungi. When the particulate is a human cell, the human cell may be an epithelial cell, for example, a columnar epithelial cell primarily derived from the nasal cavity and a squamous epithelial cell primarily derived from the oral cavity. The human cell may also be a cellular responder of the immune system, for example, neutrophils, eosinophils, lymphocytes, monocytes, macrophages, mast cells, and histocytes.

[0322] For some applications, such as shown in Figs. 31 and 3K, detecting the presence of the biological particulate trapped by filter 60 comprising using lateral flow test strip 1799 (e.g., a lateral flow immunoassay test strip) to detect the presence of the biological particulate trapped by filter 60. The lateral flow test strip is optionally contained in a housing 1710 (e.g., comprising a cartridge 1789 (also known as a cassette) or a card 3294, such as described with reference to Figs. 34E-F of above-mentioned PCT Publication WO 2023 / 131948), or implemented as a dipstick 1757, as is known in the lateral flow art, such as shown in Fig. 3K.

[0323] For some applications, filter-withdrawal shaft 1672 is not pre-coupled to filter 60 (configuration not shown, but optionally may be similar to the configuration described hereinbelow with reference to Figs. 26A-E of above-mentioned PCT Publication WO 2023 / 131948, mutatis mutandis). Instead, the filter- withdraw al shaft is advanced within internal plunger space 1686 (and optionally inserted into internal plunger space 1686) and coupled to filter 60 after plunger 1640 has been inserted into tubular container 1630 (and optionally been moved within tubular container 1630 to push the at least a portion of liquid specimen sample 22 through filter 60).

[0324] For some applications, the method further comprises bathing filter 60 with liquid 1030 within filter-collection receptacle 1650 (or extraction tube 1718, if provided) after filter 60 has been advanced into filter-collection receptacle 1650 (and into extraction tube 1718, if provided). For example, the liquid 1030 may be selected from the group consisting of: a lysis buffer, an extraction buffer, saline solution, a transport medium, and one or more reagents, such as one or more reagents for use in a lateral flow test.

[0325] In any of the applications of the present invention described herein, liquid 1030 may comprise two or more liquids that are combined (and optionally mixed together), a solid (e.g., a powder) and a liquid that are combined (and optionally mixed together), or two solids (e.g., two powders) that are combined (and optionally mixed together), typically during the testing procedure, for example as described in above-mentioned PCT Publication WO 2024 / 013747 to Feldman et al. with reference to Figs. 27A-C thereof, or as described in above-mentioned PCT Publication WO 2023 / 131948 with reference to Figs. 32B and 34A thereof. In any of the applications of the present invention described herein, liquid 1030 may comprise one or more liquids that are combined with a solid, such as a powder (and optionally mixed together), typically during the testing procedure; for example, the powder may be provided contained within one of the tubes described herein, such as one of the extraction tubes described herein.

[0326] Reference is now made to Figs. 5A-E, which are schematic cross-sectional illustrations of a sampling device 1720 for concentrating liquid specimen sample 22 and a method of using sampling device 1720, in accordance with respective applications of the present invention. Other than as described hereinbelow, sampling device 1720 is generally similar to sampling device 1620 described hereinabove with reference to Figs. 1A-3D, and may implement any of the features thereof, mutatis mutandis. Like reference numerals refer to like parts.

[0327] Similar to sampling device 1620, sampling device 1720 typically comprises a filtration assembly 1724, which may have any of the properties described hereinabove. Filtration assembly 1724 comprises tubular container 1630, a plunger 1740, and filter 60, which may have any of the properties described hereinabove with reference to Figs. 1A- 3D. However, sampling device 1720 does not comprise a filter-collection receptacle configured or disposed in a similar manner to filter-collection receptacle 1650. Nevertheless, sampling device 1720 may optionally comprise extraction tube 1718.

[0328] Plunger head 1742 is shaped so as to define a plunger-head opening 1744 through plunger head 1742 and into an internal plunger space 1786 of a plunger rod 1782. A proximal end of plunger rod 1782 is shaped so as to define a plunger- space proximal opening 1790 of internal plunger space 1786.

[0329] Sampling device 1720 comprises a withdrawer 1792, which comprises a filterwithdrawal shaft 1772, which includes a distal portion that is directly or indirectly coupled to filter 60, and which is disposed passing through internal plunger space 1786. Exemplary ways in which distal portion 1708 of filter-withdrawal shaft 1772 may be directly or indirectly coupled to filter 60 include, but are not limited to:

[0330] • distal portion 1708 of filter-withdrawal shaft 1772 may be directly coupled to filter 60, such as shown in Fig. 4, e.g., by an adhesive and / or by distal plate 1671, which may be fixed, e.g., pinned, to the distal end of the distal portion of the filterwithdrawal shaft; and

[0331] • distal portion 1708 of filter- withdraw al shaft 1772 may be indirectly coupled to filter 60, such as shown in Fig. 4 for filter-withdrawal shaft 1672, e.g., by a rod that is fixed to the distal end of the distal portion of the filter-withdrawal shaft and optionally further by an adhesive and / or by distal plate 1671 which may be integral with the rod or fixed to the rod.

[0332] It will be appreciated by persons skilled in the art who have read the present application that the distal portion of the filter- withdrawal shaft may be directly or indirectly coupled to the filter in additional ways, all of which are within the scope of the present invention. For some applications, withdrawer 1792 further comprises a shaft handle 1705, which is coupled to a proximal portion of filter-withdrawal shaft 1772. Optionally, shaft handle 1705 is shaped as a wing nut.

[0333] Sampling device 1720 is configured such that proximal withdrawal of filterwithdrawal shaft 1772 out of internal plunger space 1786, while plunger head 1742 and filter support 1662 remain within tubular container 1630, pulls filter 60 into internal plunger space 1786 via plunger-head opening 1744 (which is defined by a central opening of filter support 1662) and out of internal plunger space 1786 via plunger-space proximal opening 1790, and removes filter-withdrawal shaft 1772 and filter 60 from filtration assembly 1724. At least a portion of filter 60 is typically bunched up, such as into a flower- like arrangement, from the filter's initial flat shape while disposed on filter support 1662.

[0334] Typically, but not necessarily, after filter-withdrawal shaft 1772 and filter 60 have been removed from filtration assembly 1724, filter 60 and at a portion of filter-withdrawal shaft 1772 are inserted into extraction tube 1718, such as shown in Fig. 5E. As mentioned below, the bunching up of at least a portion of filter 60 may help facilitate this insertion; in some respects, the bunched-up filter may function somewhat analogously to a conventional swab. One or more reagents may also be placed in the extraction tube 1718, before or after insertion of filter 60, as known in the diagnostic testing arts. Optionally, extraction tube 1718 implements all or a portion of the techniques described hereinabove with reference to Figs. 16A-C in PCT Publication WO 2022 / 149135 to Feldman et al., mutatis mutandis.

[0335] Reference is now made to Fig. 6, which is a schematic illustration of a sampling device 2520 comprising a filter support 2662, in accordance with an application of the present invention. Filter support 2662 may alternatively be implemented (a) in the sampling devices described in the patent application publications and patents incorporated herein by reference; (b) in the other sampling devices described herein; or (c) in other sampling devices known in the art. Sampling device 2520 comprises a filtration assembly 2524, which is similar in many respects to filtration assemblies 1624, 1724, 2224A, and 2224B, described herein with reference to Figs. 1A-3D, Figs. 5A-E, Figs. 16A-C, and Figs. 17A-B and 18A-D, respectively, and may implement any of the features thereof, mutatis mutandis.

[0336] Sampling device 2520 comprises a pressure source 2596. For some applications, such as illustrated, pressure source 2596 comprises a source of gas 2204, which is configured to provide gas 2208 into a space 2233 defined within filtration assembly 2524 outside a tubular container 2030 of filtration assembly 2524. Filtration assembly 2524 is configured such that providing of gas 2208 into space 2233, when liquid specimen sample 22 is contained in tubular container 2030 and filter 60 is disposed on the support surface, pushes at least a portion of liquid specimen sample 22 through filter 60 and filtrate-passage openings 1668 and into waste liquid receptacle 1656.

[0337] For example, source of gas 2204 may comprise one or more substances 2205 that generate gas 2208, such as when combined with each other and / or with a liquid, such as liquid of liquid specimen sample 22. For some applications, the one or more substances 2205 may comprise a solid substance 2205A and a liquid substance 2205B. For example, solid substance 2205A may comprise sodium bicarbonate and liquid substance 2205B may comprise an acidic solution (e.g., comprising acetic acid or citric acid), which generate carbon dioxide gas 2208 when combined; or solid substance 2205A may comprise sodium bicarbonate and anhydrous citric acid and liquid substance 2205B may comprise water, which generate carbon dioxide gas 2208 when combined. Alternatively, the one or more substance 2205 may comprise one or more substances that are provided in combination, such as sodium bicarbonate and anhydrous citric acid, which generate carbon dioxide gas 2208 when combined with liquid of liquid specimen sample 22 (configuration not shown). Further alternatively, the one or more substance 2205 may comprise two or more liquids. In these configurations, tubular container 2030 typically forms a fluid-tight movable seal with an inner surface 2021 of a lateral wall 2023 of a container housing 2022 of filtration assembly 2524, for example using an O-ring 2025. For example, solid substance 2205 A may comprise 0.5 - 2 g of sodium bicarbonate and liquid substance 2205B may comprise 1 - 5 mL of acetic acid.

[0338] Source of gas 2204 may comprise at least one container 2206, such as a pouch, in which typically one of the one or more substances 2205 is stored (e.g., either solid substance 2205A or liquid substance 2205B), isolated from the other of the one or more substances 2205 in applications in which two or more substances 2205 are provided and combined with each other.

[0339] Alternatively, source of gas 2204 may comprise a compressed gas container, such as described in above-referenced PCT Publication WO 2024-013747 to Feldman et al., with reference to Figs. 21A-C thereof, and / or hereinbelow with reference to Figs. 16A-C. As mentioned above, source of gas 2204 is configured to provide gas 2208 into space 2233 defined within filtration assembly 2524. For some applications, space 2233 is a space 2234 defined between (a) proximally-facing internal surface 2108 of container housing 2022 and (b) an external surface 2106 of tubular container 2030 that is defined by a distal end 2107 of tubular container 2030. Space 2234 is typically airtight. Providing gas 2208 into space 2234 increases the pressure in space 2234, thereby proximally moving tubular container 2030 proximally with respect to plunger head 1742 (and typically with respect to container housing 2022). This proximal movement of tubular container 2030 pushes a portion of liquid specimen sample 22 through filter 60 and into waste liquid receptacle 1656. This proximal movement of tubular container 2030 also increases the volume of space 2234, which thus defines a variable volume.

[0340] For some applications, filtration assembly 2524 is configured such that movement of plunger head 1742 within tubular container 2030 causes source of gas 2204 to provide gas 2208. Typically, in these configurations, the movement of plunger head 1742 within tubular container 2030 is insufficient to push a meaningful portion of liquid specimen sample 22 through filter 60. For other applications, source of gas 2204 is configured to provide gas 2208 upon manual activation of source of gas 2204.

[0341] For some of these applications, the movement of plunger head 1742 within tubular container 2030 causes distal movement of tubular container 2030 within container housing 2022. This distal movement of tubular container 2030 within container housing 2022 may open container 2206 of source of gas 2204. For example, this distal movement of tubular container 2030 may open container 2206 by breaching (e.g., rupturing, penetrating, and / or tearing) container 2206, e.g., by pushing one or more spikes 2242 into a wall of container 2206. Optionally, the one or more spikes 2242 are defined by a distal end of a shaft 2238, and the proximal end of shaft 2238 is pushed distally by distal end 2107 of tubular container 2030. Opening of container 2206 causes a reaction that generates gas 2208, such as described above.

[0342] For other applications, pressure source 2596 comprises a plunger, such as plunger 1640 or plunger 1740, described hereinabove with reference to Figs. 1A-3D and 5A-E, respectively.

[0343] Reference is additionally made to Figs. 7A-C, which are schematic illustrations of respective portions of filter support 2662, in accordance with an application of the present invention. Figs. 7A shows all of the elements of filter support 2662 described herein. For illustrative purposes only, Fig. 7B omits filter 60, to better show a fluid-permeable layer 2604, and Fig. 7C omits both filter 60 and fluid-permeable layer 2604, to better show a rigid solid base 2664, as described below.

[0344] Reference is yet additionally made to Figs. 8A-B, which are schematic illustrations of a portion of filter support 2662 before and after perforation of filter 60, respectively, as described below, in accordance with an application of the present invention.

[0345] Reference is also made to Figs. 8C-D, which are schematic illustrations of another configuration of a portion of filter support 2662 before and after perforation of filter 60, respectively, as described below, in accordance with an application of the present invention.

[0346] For some applications, as described above for other sampling devices, sampling device 2520 shown in Fig. 6-8D comprises filtration assembly 2524, which comprises:

[0347] • tubular container 2030, which is shaped so as to define inner wall 2033 and proximal container opening 2036 for receiving liquid specimen sample 22;

[0348] • plunger 1740, which (a) comprises plunger head 1742 and plunger rod 1782, which has a distal end portion to which plunger head 1742 is coupled, and (b) is insertable into tubular container 2030 via proximal container opening 2036, such that a lateral surface of plunger head 1742 forms a fluid-tight movable seal with inner wall 2033 of tubular container 2030;

[0349] • waste liquid receptacle 1656;

[0350] • filter support 2662; and

[0351] • filter 60.

[0352] Filter support 2662 comprises:

[0353] • a rigid solid base 2664, which, as labeled in Figs. 6 and 7B, includes (i) a first portion 2666, which is shaped so as to define a plurality of filtrate-passage openings 1668 through rigid solid base 2664 into waste liquid receptacle 1656, and (ii) a second portion 2668, which is shaped so as to define a pressure-release opening 2602 through rigid solid base 2664 into waste liquid receptacle 1656; and

[0354] • fluid-permeable layer 2604, fixed to rigid solid base 2664 covering first portion 2666 (on a distal side of rigid solid base 2664) without covering second portion 2668 (which is shaped so as to define pressure-release opening 2602, as described above).

[0355] Fluid-permeable layer 2604 typically is configured to allow lateral flow of liquid specimen sample 22 within fluid-permeable layer 2604, so as to enable passage, to filtratepassage openings 1668, even of portions of liquid specimen sample 22 that pass through filter 60 at locations not aligned with filtrate-passage openings 1668. For example, fluid- permeable layer 2604 may comprise a non-woven fabric, a woven fabric, or a mesh.

[0356] For some applications, fluid-permeable layer 2604 has a porosity greater than a porosity of filter 60.

[0357] Fluid-permeable layer 2604 and second portion 2668 of rigid solid base 2664 together are shaped so as to define a support surface 2659, on which filter 60 is removably disposed.

[0358] The filtration assembly is configured such that:

[0359] • pressurizing liquid specimen sample 22 in tubular container 2030 at a first pressure less than a threshold pressure pushes a first portion of liquid specimen sample 22 (a) through filter 60, (b) (1) partially through fluid-permeable layer 2604 and filtrate-passage openings 1668 and (2) partially through pressure -release opening 2602, and (c) into waste liquid receptacle 1656, and

[0360] • pressurizing liquid specimen sample 22 in tubular container 2030 at a second pressure greater than the threshold pressure (i) perforates a portion 2606 of filter 60 covering pressure-release opening 2602, such as shown in Fig. 8B, and (ii) pushes a second portion of liquid specimen sample 22 through perforated portion 2606 of filter 60 and pressure-release opening 2602, and into waste liquid receptacle 1656.

[0361] Typically, the pushing of the second portion of liquid specimen sample 22 through filter 60 at the second pressure does not cause the second portion of liquid specimen sample 22 to perforate other portions of filter 60 removably disposed on fluid-permeable layer 2604 covering first portion 2666.

[0362] The pressurizing of liquid specimen sample 22 in tubular container 2030 is typically caused by relative motion of plunger head 1742 with respect to tubular container 2030, either (a) manually driven by the user, such as in the configurations described hereinabove with reference to Figs. 1 A-3D and 5A-D, or (b) driven by the device by providing gas 2208, such as in the configurations described hereinbelow with reference to Figs. 6 and 14A-F.

[0363] During use of the filtration assembly, liquid specimen sample 22 in tubular container 2030 may or may not be pressurized at the second pressure greater than the threshold pressure (for example, depending on the degree of clogging of the filter and / or the rate of motion of plunger head 1742 with respect to tubular container 2030). Typically, if the liquid specimen sample 22 is pressurized at the second pressure, the second portion of liquid specimen sample 22 is pushed through filter 60 after the first portion of liquid specimen sample 22 is pushed through filter 60. Typically, once filter 60 has been perforated, any additional liquid specimen sample 22 passes entirely, or substantially entirely, through perforated portion 2606 of filter 60 and pressure-release opening 2602, and does not pass through the intact portion of the filter.

[0364] The perforation of filter 60 allows completion of the plunger stroke even if the filter becomes too clogged to allow material passage of the liquid specimen sample. For example, the filter may become clogged if liquid specimen sample 22 is gargled fluid containing a substantial amount of mucus. Even though completion of the plunger stroke after perforation of the filter will generally not capture additional biological particulate on the filter, completion of the plunger stroke may be desirable to allow the user to properly follow the instructions for use, which may specify completion of the plunger stroke.

[0365] Completion of the plunger stroke may also be desirable in configurations in which the filtration assembly controls the plunger stroke. For example, completion of the plunger stroke may be desirable in configurations in which the device includes safety and / or efficacy mechanism that require completion of the plunger stroke to enable subsequent steps of the testing procedure, such as removal of the filter from the filtration assembly.

[0366] For some applications, pressure-release opening 2602 has a cross-sectional area greater than an average cross-sectional area of filtrate-passage openings 1668. Alternatively, the cross-sectional area of pressure-release opening 2602 is less than or equal to the average cross-sectional area of filtrate-passage openings 1668.

[0367] For some applications, first portion 2666 of rigid solid base 2664 is shaped so as to define at least 5 filtrate-passage openings 1668, such as 5 -1,000, e.g., 10 -100 filtratepassage openings.

[0368] For some applications, respective portions of support surface 2659 defined by fluid- permeable layer 2604 and second portion 2668 of rigid solid base 2664 are flush with each other, such as shown. Alternatively, they are not flush with each other (configuration not shown).

[0369] For some applications, rigid solid base 2664 is shaped so as to define no more than five pressure-release openings 2602 through rigid solid base 2664 into waste liquid receptacle 1656, such as exactly one pres sure -release opening 2602 through rigid solid base 2664 into waste liquid receptacle 1656, such as shown.

[0370] For some applications, such as shown in Figs. 8C-D, filtration assembly 2524 further comprises a dissolvable plug 2608 disposed in pressure-release opening 2602. Dissolvable plug 2608 comprises a material 2610 that is configured to dissolve upon exposure to liquid specimen sample 22 (via filter 60) for at least a threshold amount of time after commencement of exposure to liquid specimen sample 22. Typically, the threshold amount of time is at least 30 seconds, no more than 300 seconds, (e.g., no more than 180 seconds), and / or 30 - 300, e.g., 30 - 180 seconds, such as 30 - 90 seconds, e.g., 30 - 60 seconds. Prior to the dissolving of material 2610, dissolvable plug 2608 prevents passage of liquid specimen sample 22 through pressure -release opening 2602 even when liquid specimen sample 22 is pressured at the second pressure described above, and thereby prevents perforation of portion 2606 of filter 60 covering pres sure -release opening 2602, as described above. Thus, dissolvable plug 2608, prior to the dissolving of material 2610 during an initial portion of the filtration, prevents passage of liquid specimen sample 22 through pressure-release opening 2602 even if the pressure of the liquid increases rapidly even though filter 60 has not yet clogged. After the dissolving of material 2610, pressurizing liquid specimen sample 22 in tubular container 2030 at the second pressure perforates portion 2606 of filter 60 covering pressure-release opening 2602, such as shown in Fig. 8D.

[0371] For some applications, pressure-release opening 2602 narrows at a downstream end portion 2612 thereof, in order to prevent the pressure applied to dissolvable plug 2608 by liquid specimen sample 22 (via filter 60) from ejecting dissolvable plug 2608 from downstream end portion 2612 prior to the dissolving of dissolvable material 2610.

[0372] For some applications, such as shown in Figs. 6-8D, plunger rod 1782 is shaped so as to define waste liquid receptacle 1656 within plunger rod 1782, and plunger head 1742 comprises filter support 2662. For some of these applications, such as shown in Figs. 6- 8D, the sampling device further comprises container housing 2022, described hereinabove, and tubular container 2030 is disposed at least partially within container housing 2022, such that the tubular container 2030 is moveable with respect to container housing 2022.

[0373] For other applications, an internal distal bottom surface of the tubular container comprises filter support 2662, such as described hereinabove regarding filter support 1662 with reference to Figs. 15A-F, mutatis mutandis.

[0374] Reference is again made to Fig. 6. For some applications, filtration assembly 2524 further comprises a pressure-responsive valve 2552 that is configured to limit a pressure within space 2233 (e.g., space 2234). Limiting the pressure may be beneficial if filter 60 becomes overly clogged during an early portion of the filtration, such as if liquid specimen sample 22 is more viscous than typical samples. For example, for applications in which liquid specimen sample 22 is gargled fluid, the sample may include more mucus than typical gargled fluid samples. If filter 60 becomes overly clogged during the early portion of the filtration, the pressure within space 2233 (e.g., space 2234) may exceed desired values, because gas 2208 builds up as source of gas 2204 continuously provides more gas into space 2233, and the gas has reduced ability to push the at least a portion of liquid specimen sample 22 through filter 60 and the filtrate -passage openings and into waste liquid receptacle 1656. The excessive pressure may undesirably force liquid specimen sample 22 through the clogged filter (e.g., exceeding the operating pressure of the filter), resulting in tearing of the filter and / or an increased rate of undesired passage of biological particulate through the filter, rather than the filter trapping the biological particulate. The limiting of the pressure within space 2233 by pressure-responsive valve 2552 prevents the pressure within space 2233 from increasing undesirably, thereby solving this problem.

[0375] Pressure-responsive valve 2552 may be responsive to the pressure within space 2233 by closing or opening, or closing or opening to a greater or lesser extent, based on the pressure within space 2233. Optionally, pressure -responsive valve 2552 is configured to constrain the pressure within space 2233; to set a maximum value of the pressure within space 2233; and / or to set a maximum pressure differential between the pressure within space 2233 and the pressure at a location outside space 2233. For example, the location outside space 2233 may be gas-release regulation chamber 2232 (in configurations in which gas-release regulation chamber 2232 is provided), compressed gas container 2240 (in configurations in which compressed gas container 2240 is provided), or the atmosphere 2978 outside the filtration assembly, depending on the particular configuration of the filtration assembly and the pressure-responsive valve. For some applications, such as shown in Fig. 6, pressure-responsive valve 2552 comprises a pressure relief valve 2556, which is configured to release a portion of gas 2208 from space 2233 (e.g., space 2234) when the pressure within the space exceeds a threshold pressure. For example, pressure relief valve 2556 may be configured to release the portion of gas 2208 from the space to the atmosphere 2978 outside the filtration assembly 2524, such as shown. Typically, the threshold is generally pre-determined, although it might vary slightly based on the pressure outside the space, e.g., atmospheric pressure. Pressure relief valve 2556, when in a closed state, blocks flow of gas 2208 from the space. Pressure relief valve 2556, when in an open state, releases gas 2208 from the space, such as shown in Fig. 6.

[0376] Optionally, pressure-responsive valve 2552 may implement any of the techniques described in above-mentioned International Application PCT / IL2024 / 050679, including with reference to Figs. 24A-C, 25A-B, and 26A-C thereof and / or Figs. 27A-B thereof, mutatis mutandis.

[0377] Reference is now made to Figs. 9A-E, which are schematic illustrations of a sampling device 2720 for concentrating liquid specimen sample 22, and a method of using sampling device 2720, in accordance with an application of the present invention.

[0378] Reference is further made to Figs. 10A and 10B, which are schematic isometric and cross-sectional illustrations of sampling device 2720, in accordance with an application of the present invention.

[0379] Reference is still further made to Figs. 10C-D, which are exploded schematic illustrations of a portion of sampling device 2720, from two different directions, in accordance with an application of the present invention.

[0380] Reference is additionally made to Fig. 11, which is a cross-sectional schematic illustration of a portion of sampling device 2720, in accordance with an application of the present invention.

[0381] Other than as described hereinbelow, sampling device 2720 is generally similar to sampling device 1620 described hereinabove with reference to Figs. 1A-3D, and may implement any of the features thereof, mutatis mutandis. Like reference numerals refer to like parts. Optionally, sampling device 2720 implements any of the techniques of the other sampling devices described herein, and / or described in any of the patent applications and patent application publications incorporated herein by reference. In sampling device 2720:

[0382] • filter 60 is a main (target) filter 60,

[0383] • filter-withdrawal shaft 1672 is a main-filter-withdrawal shaft 1672,

[0384] • filter support 1662 (if provided) is a main filter support 1662, which is shaped so as to define a main distal (or upstream) support surface 1659 and a plurality of main filtrate-passage openings 1668 through main filter support 1662 into waste liquid receptacle 1656, and

[0385] • filter-collection receptacle 1650 (if provided) is a main-filter-collection receptacle 1650.

[0386] Sampling device 2720 comprises a filtration assembly 2724, which, other than as described below, is similar to filtration assembly 1624, and may implement any features thereof, mutatis mutandis, as well as of the filtration assemblies of the other sampling devices described herein, and / or described in any of the patent applications and patent application publications incorporated herein by reference.

[0387] Sampling device comprises pressure source 2596, described hereinabove with reference to Fig. 6. Pressure source 2596 may comprise plunger 1640, as illustrated, or may comprise source of gas 2204, such as described hereinabove with reference to Fig. 6.

[0388] Filtration assembly 2724 further comprises a prefilter 2763, which is fixed to plunger head 1642 distal to main filter 60. Plunger 1640 is insertable into tubular container 1630 via proximal container opening 1632, thereby inserting main filter 60 and prefilter 2763 into the tubular container and forming a fluid-tight movable seal between a lateral surface of the plunger head and the inner wall of the tubular container. Filtration assembly 2724 is configured such that movement of the plunger head within the tubular container, when liquid specimen sample 22 is contained in the tubular container and main filter 60 is removably disposed on the distal end of plunger head 1642 in tubular container 1630, pushes at least a portion of liquid specimen sample 22 through prefilter 2763 and main filter 60.

[0389] Sampling device 2720 is configured such that while plunger head 1642 is within tubular container 1630, proximal withdrawal of main-filter-withdrawal shaft 1672 out of internal plunger space 1686 pulls main filter 60 into internal plunger space 1686 via plunger-head opening 1644 and out of internal plunger space 1686 via plunger-space proximal opening 1690 (labeled in Fig. 9E), and removes main-filter- withdraw al shaft 1672 and main filter 60 from filtration assembly 2724, while leaving prefilter 2763 fixed to plunger head 1642.

[0390] The prefiltration performed by prefilter 2763 may remove viscous components of liquid specimen sample 22, such as mucus. This removal may reduce the clogging of main filter 60, and thus allow main filter 60 to filter a greater volume at a lower pressure, resulting in more efficient filtration. Only main filter 60, and not prefilter 2763, are pulled out of filtration assembly 2724, to enable testing of main filter 60 for particulate trapped by main filter 60. In general, the viscous components of liquid specimen sample 22 captured by prefilter 2763 are of less interest for testing for particulate.

[0391] Typically, prefilter 2763 has a greater average pore size than the pore size of main filter 60, such as at least 5 times the pore size of main filter 60, e.g., at least 10 times the size.

[0392] For some applications, prefilter 2763 has a pore size of at least 1.2 microns, no more than 20 microns, and / or 1.2 - 20 microns, e.g., 6 - 12 microns, e.g., 8 microns. Main filter 60 may have any of the pore sizes and / or other characteristics described hereinabove and / or in the table below.

[0393] The following tables provide exemplary characteristics of prefilter 2763 and main filter 60, by way of example and not limitation.

[0394] For some applications, plunger head 1642 is shaped so as to define (integral with other portions of plunger head 1642 or as a separate piece attached to other portions of plunger head 1642) a prefilter support 2765, which is shaped so as to define a prefilter distal support surface 2767 and a plurality of prefilter filtrate-passage openings 2769 through prefilter support 2765. Prefilter support 2765 is disposed distal to main filter 60. Prefilter 2763 is disposed on prefilter distal support surface 2767 of prefilter support 2765.

[0395] For some applications, sampling device 2720 implements, mutatis mutandis, the reversible filter-clamping techniques of sampling devices 1820 or 1920, described in PCT Publication WO 2023 / 131948 to Levitz et al., which is incorporated herein by reference, with reference to Figs. 11A-13F and Figs. 14A-16E thereof, respectively. In these applications, sampling device 2720 is typically configured to reversibly filter-clamp only main filter 60, and not prefilter 2763, as can be seen, for example, in the transition between Fig. 9B and 9C of the present application.

[0396] Sampling device 2720 may optionally comprise fluid-permeable layer 2604, described hereinabove with reference to Figs. 7A-C and 8A-B; alternatively, sampling device 2720 does not comprise fluid -permeable layer 2604. Reference is now made to Fig. 11, which is a schematic illustration of a portion of another configuration of sampling device 2720, in accordance with an application of the present invention. In this configuration, sampling device 2720 comprises two prefilters 2763 A and 2763B. Optionally, the more distal of the two prefilters (2763B) has a greater average pore size than the more proximal of the two prefilters (2763A).

[0397] Reference is now made to Figs. 12A-D, which are schematic cross-sectional illustrations of a sampling device 2820, 2820A for concentrating liquid specimen sample 22, and a method of using sampling device 2820, 2820A, in accordance with an application of the present invention.

[0398] Reference is further made to Figs. 13A-D, which are schematic cross-sectional illustrations of a sampling device 2820, 2820B for concentrating liquid specimen sample 22, and a method of using sampling device 2820, 2820B, in accordance with an application of the present invention.

[0399] Reference is still further made to Figs. 14A-F, which are schematic cross-sectional illustrations of a sampling device 2820, 2820C for concentrating liquid specimen sample 22, and a method of using sampling device 2820, 2820C, in accordance with an application of the present invention.

[0400] Figs. 12A, 13A, and 14A shows the sampling devices after filtration has already been performed, similar to the state shown in Figs. 3B, 5B, and 6.

[0401] Other than as described hereinbelow, sampling device 1820 is generally similar to the other sampling devices described herein, and may implement any of the features thereof, mutatis mutandis. Like reference numerals refer to like parts. In particular, sampling devices 1820, 1820A and 1820, 1820B are generally similar to sampling device 1620, described hereinabove with reference to Figs. 1 A-3D, and sampling device 2720, described hereinabove with reference to Figs. 9A-11, and may implement any of the features thereof, mutatis mutandis. Optionally, sampling device 2820 implements any of the techniques of the other sampling devices described herein, and / or described in any of the patent applications and patent application publications incorporated herein by reference.

[0402] Sampling devices 2820, 2820A, 2820B, 2820C comprise filtration assemblies 2824, 2824A, 2824B, 2824C, respectively. Filtration assembly 2824 comprises:

[0403] • tubular container 1630, which is shaped so as to define inner wall 1634 (labeled in Fig. 3A) and proximal container opening 1632 for receiving liquid specimen sample 22; main filter 60;

[0404] • prefilter 2763, which is disposed upstream of main filter 60 in fluid communication with main filter 60;

[0405] • a withdrawer 2792 comprising one or more filter-withdrawal shafts 2794, which are disposed along an axis 2796 of withdrawer 2792 (labeled in Fig. 12C), and are coupled to a main-filter coupling portion 2802 of main filter 60 and a prefilter coupling portion 2804 of prefilter 2763; and

[0406] • pressure source 2596, which is configured, when liquid specimen sample 22 is contained in tubular container 1630 and main filter 60 is in fluid communication with liquid specimen sample 22 via prefilter 2763, to push at least a portion of liquid specimen sample 22 downstream through prefilter 2763 and main filter 60.

[0407] Sampling device 2820 is configured such that withdrawal of the one or more filterwithdrawal shafts 2794 out of filtration assembly 2824:

[0408] • pulls main filter 60 and prefilter 2763 from filtration assembly 2824, and

[0409] • bunches up at least respective portions of main filter 60 and prefilter 2763, such that at least a part 2771 of the bunched-up portion of prefilter 2763 is disposed outside main filter 60 (i.e., outside main filter 60 along axis 2796, rather than within main filter 60; "outside" should not be construed as relating to the relative radial locations of main filter 60 and prefilter 2763 with respect to axis 2796).

[0410] Pressure source 2596 may implement any of the features thereof described hereinabove with reference to Fig. 6. Pressure source 2596 may comprise plunger 1640, as illustrated in Figs. 12A-D and 13A-D, or may comprise source of gas 2204, such as illustrated in Figs. 14A-F. Source of gas 2204 may implement any of the features described hereinabove with reference to Fig. 6, and / or any of the features described in International Application PCT / IL2024 / 050679, filed July 11, 2024, which is assigned to the assignee of the present application and incorporated herein by reference. Prefilter 2763 may implement any of the features thereof described hereinabove with reference to Figs. 9A-11, including, but limited to pore size and the exemplary characteristics provided in the tables.

[0411] For some applications, withdrawer 2792 is withdrawn from the bottom the filtration assembly, rather than through the plunger head.

[0412] For some applications, such as labeled in Fig. 12D, part 2771 of the bunched-up portion of prefilter 2763 has a length LI, measured along axis 2796:

[0413] • of at least 3 mm, such as at least 5 mm,

[0414] • less than 20 mm, such as less than 10 mm,

[0415] • equal to at least 10%, e.g., at least 20%, such as at least 25% of a length L2 of an entirety of the bunched-up portion of prefilter 2763, measured along axis 2796, and / or

[0416] • less than 75%, e.g., less than 50%, such as less than 25%, of the length L2 of the entirety of the bunched-up portion of prefilter 2763.

[0417] Alternatively or additionally, for some applications, such as labeled in Fig. 12D, sampling device 2820 is configured such that, at least upon the withdrawal, a distance D between a first location of main-filter coupling portion 2802 along axis 2796 and a second location of prefilter coupling portion 2804 along axis 2796 is at least 3 mm, such as at least 5 mm, and / or no more than 20 mm, such as no more than 10 mm.

[0418] For some applications, an area of prefilter 2763 equals 50% - 150%, such as 90% - 110%, e.g., 100%, of an area of main filter 60.

[0419] For some applications, the one or more filter-withdrawal shafts 2794 are coupled to respective central portions of main filter 60 and prefilter 2763, such as shown.

[0420] For some applications, sampling device 2820 is configured such that withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824 bunches up at least respective portions of main filter 60 and prefilter 2763 into respective flower-like arrangements. Alternatively or additionally, the at least a portions of main filter 60 and prefilter 2763 are bunched up so as to have a plurality of folds, which optionally are soft folds (i.e., not creased). In this sense, the bunched-up filters may be considered to be shaped generally as a soft-pleated skirt without an opening at the waist. In general, the flower-like bunched-up shape of the filters may create open soft folds, rather than crumpled and / or closed folds that would create closed spaces that liquid cannot reach.

[0421] Reference is made to Figs. 13A-D. For some applications, sampling device 2820, 2820B is configured such that the withdrawal bunches up the at least respective portions of main filter 60 and prefilter 2763, such that an entirety of the bunched-up portion of prefilter 2763 is disposed outside main filter 60.

[0422] Reference is made to Figs. 12A-D and 13A-D. For some applications, sampling device 2820, 2820A, 2820B is configured such that the distance D between a first location of main-filter coupling portion 2802 along axis 2796 and a second location of prefilter coupling portion 2804 along axis 2796 increases during the withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824.

[0423] For some of these applications, the one or more filter-withdrawal shafts 2794 comprise:

[0424] • a first filter-withdrawal shaft 2794B that is coupled to main-filter coupling portion 2802 of main filter 60; and

[0425] • a second filter-withdrawal shaft 2794 A that is coupled to prefilter coupling portion 2804 of prefilter 2763.

[0426] First and second filter-withdrawal shafts 2794B, 2794A are configured to axially slide with respect to each other during the withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824, so as to increase the distance D.

[0427] For some applications, first filter-withdrawal shaft 2794B is nested within at least an axial portion of second filter-withdrawal shaft 2794A.

[0428] Reference is again made to Figs. 12A-D. For some applications, sampling device 2820, 2820A further comprises a flexible screen 2810, which is disposed between main filter 60 and prefilter 2763. The other sampling devices described herein, including sampling devices 2820B and 2820C, may also comprise flexible screen 2810. Alternatively, the sampling devices described herein do not comprise flexible screen 2810, such as shown in Figs. 13A-D and 14A-F.

[0429] Flexible screen 2810 is porous, and may comprise, for example, a mesh, netting, a perforated piece of material, or a fabric (e.g., a woven, knit, or knotted material of open texture). Flexible screen 2810 typically comprises a polymer or a metal.

[0430] Typically, respective surfaces of flexible screen 2810 and main filter 60 are not coupled together (although flexible screen 2810 may be coupled to main filter 60 at main- filter coupling portion 2802). Typically, respective surfaces of flexible screen 2810 and prefilter 2763 are not coupled together (although flexible screen 2810 may be coupled to prefilter 2763 at prefilter coupling portion 2804).

[0431] For some applications, an area of flexible screen 2810 equals 50% - 150%, such as 90% - 110%, e.g., 100%, of an area of main filter 60 and / or of prefilter 2763.

[0432] For some applications, sampling device 2820, 2820A is configured such that the withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824 pulls main filter 60, flexible screen 2810, and prefilter 2763 from filtration assembly 2824.

[0433] Flexible screen 2810 may serve one or both of the following functions:

[0434] • flexible screen 2810 may separate prefilter 2763 from main filter 60 during filtration, which may improve the filtration; and / or

[0435] • flexible screen 2810 may help push main filter 60 radially outward after withdrawal and bunching up of main filter 60, which slightly separates main filter 60 from prefilter 2763 and helps liquid enter between the filters during bathing of the filters during testing of the filters, for example as described herein with reference to Figs. 3E-I.

[0436] Reference is made to Figs. 14A-F. For some applications, sampling device 2820, 2820C is configured such that distance D remains constant during the withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824.

[0437] Reference is still made to Figs. 14A-F. For some applications, withdrawer 2792 comprises exactly one filter-withdrawal shaft 2794.

[0438] Reference is still made to Figs. 14A-F. For some applications, filtration assembly 2824, 2824C comprises prefilter support 2765, which is shaped so as to define prefilter distal support surface 2767 and the plurality of prefilter filtrate-passage openings 2769 through prefilter support 2765. Prefilter 2763 (and not main filter 60) is disposed on prefilter distal support surface 2767 of prefilter support 2765.

[0439] For some of these applications, sampling device 2820, 2820C is configured such that the withdrawal of the one or more filter- withdraw al shafts 2794 (e.g., the exactly one filter-withdrawal shaft 2794) out of filtration assembly 2824 pulls main filter 60 and prefilter 2763 from filtration assembly 2824, while leaving prefilter support 2765 within filtration assembly 2824, such as shown in Fig. 14F.

[0440] Reference is again made to Figs. 12A-D, 13A-D, and 14A-F. For some applications, filtration assembly 2824 is shaped so as to define therewithin waste liquid receptacle 1656. Filtration assembly 2824 comprises main filter support 1662, which is shaped so as to define (a) main distal support surface 1659, and (b) the plurality of main filtrate-passage openings 1668 through main filter support 1662 into waste liquid receptacle 1656. Main filter 60 is removably disposed on main distal support surface 1659 of main filter support 1662. Pressure source 2596 is configured, when liquid specimen sample 22 is contained in tubular container 1630 and main filter 60 is removably disposed on the main distal support surface of main filter support 1662 in tubular container 1630, to push the at least a portion of liquid specimen sample 22 through prefilter 2763, main filter 60, and the main filtrate -pas sage openings and into waste liquid receptacle 1656.

[0441] For some of these applications, sampling device 2820 is configured such that the withdrawal of the one or more filter-withdrawal shafts 2794 out of filtration assembly 2824 pulls main filter 60 and prefilter 2763 from filtration assembly 2824, while leaving main filter support 1662 within filtration assembly 2824.

[0442] Reference is again made to Figs. 14A-F. The following techniques may also be implemented in the other sampling devices described herein, including sampling devices 2820A and 2820B, described hereinabove with reference to Figs. 12A-D and 13A-D. In this configuration, wherein pressure source 2596 comprises source of gas 2204, configured to provide gas 2208 into a space 2833 defined within filtration assembly 2824, 2824B. Filtration assembly 2824, 2824B is configured such that providing of gas 2208 into space 2833, when liquid specimen sample 22 is contained in tubular container 1630 and main filter 60 is in fluid communication with liquid specimen sample 22 via prefilter 2763, pushes the at least a portion of liquid specimen sample 22 downstream through prefilter 2763 and main filter 60.

[0443] For some applications, source of gas 2204 comprises at least one container 2607, such as a first container 2607A (which, by way of example and not limitation is shown as annular), in which typically one of the one or more substances 2205 is stored (e.g., either solid substance 2205A, such as shown, or liquid substance 2205B (configuration not shown)), isolated from the other of the one or more substances 2205. For example, liquid substance 2205B may be stored in a second container 2607B, and a proximal cap 2625 may comprise a sharp surface 2609, which is configured to pierce second container 2607B and release liquid substance 2205B when proximal cap 2625 sealably closes proximal container opening 2036, as shown in Fig. 14C. Optionally, first container 2607A comprises a water- and gas-permeable wall, and / or a dissolvable wall. For some applications, filtration assembly 2624 is shaped so as to define a gasrelease regulation chamber 2632, in which source of gas 2204 is disposed. Optionally, one of the one or more substances 2205 (e.g., either solid substance 2205 A) is disposed directly in gas-release regulation chamber 2632, in which case first container 2607A is not provided. By way of example and not limitation, gas-release regulation chamber 2632 is shown as extending around a periphery of filtration assembly 2824, 2824B. Alternatively or additionally, gas-release regulation chamber 2632 may be disposed radially outward from tubular container 1630 and / or waste liquid receptacle 1656, also as shown. Gas-release regulation chamber 2632 is nearly entirely isolated from space 2833. Gas-release regulation chamber 2632 is in fluid communication with space 2833 only by one or more narrow openings 2636, which may help provide a controlled flow rate of gas 2208 into space 2833.

[0444] Optionally, filtration assembly 2624 comprises one or more tubes 2611, e.g., coupled to proximal cap 2625, which couple space 2733 in fluid communication with gas- release regulation chamber 2632 via the one or more narrow openings 2636.

[0445] Reference is still made to Figs. 14A-F. In configurations in which pressure source 2596 comprises source of gas 2204, liquid specimen sample 22 typically does not pool or get trapped in the space between prefilter 2763 and main filter 60, because gas 2208 typically enters this space after liquid specimen sample 22 has passed through prefilter 2763. Nevertheless, if some of liquid specimen sample 22 were to remain in this space, generally a sufficient amount of liquid specimen sample 22 is filtered for testing purposes.

[0446] Reference is still made to Figs. 14A-F. For some applications, main filter support 1662, prefilter support 2765, or both main filter support 1662 and prefilter support 2765 are shaped so as to define one or more pressure-release openings 2602, such as described hereinabove with reference to Figs. 7A-8D. In configurations in which at least main filter support 1662 is shaped so as to define one or more pressure -release openings 2602, if, at any point during filtration, main filter 60 clogs, but prefilter 2763 does not clog, the one or more pressure -release openings 2602 of main filter support 1662 allow the liquid to bypass main filter 60, such that filtration can continue to occur through prefilter 2763.

[0447] Reference is made to again made to Figs. 13A-D. Optionally, filtration assembly 2624, 2624B further comprises a second prefilter 2763B, such as described hereinabove with reference to Fig. 11. The other filtration assemblies described herein, including with reference to Figs. 12A-D and 14A-F may also comprise second prefilter 2763B. Reference is again made to Figs. 13A-D. For some applications, filtration assembly 2824, 2842B comprises a filter-collection receptacle 2750 that is configured to telescopically extend. Alternatively, filtration assembly 2824, 2842B comprises filtercollection receptacle 1650, or does not comprise a filter-collection receptacle.

[0448] Reference is again made to Figs. 12A-D, 13A-D, and 14A-F. For some applications, after main filter 60 and prefilter 2763 have been removed from the filtration assembly, and are optionally contained within filter-collection receptacle 1650 (or 2750), both main filter 60 and prefilter 2763 are tested, typically simultaneously, for the presence of trapped particulate, such as using the techniques described hereinabove with reference to Figs. 3E- I, diagnostic testing techniques described in any of the patent application publications and patents incorporated herein by reference, and / or known in the art.

[0449] For example, the inventors have observed that when testing urine for sexually transmitted infections (STIs), such as gonorrhea and / or chlamydia, using a lateral flow immunoassay test strip, testing prefilter 2763, in addition to main filter 60, may increase sensitivity. For example, for testing for gonorrhea, main filter 60 may have a pore size of 0.4 - 0.8 microns, such as 0.45 microns, and / or prefilter 2763 may have a pore size of 5 - 12 microns, such as 8 microns.

[0450] Reference is now made to Figs. 15A-B, which are schematic illustrations of respective filter assemblies 2900A and 2900B, respectively, in accordance respective applications of the present invention. Filter assembly 2900A comprises main filter 60 and prefilter 2763, and filter assembly 2900B comprise main filter 60, but not prefilter 2763. The filter assemblies further comprise a flexible screen 2910, which is disposed upstream of prefilter 2763 in filter assembly 2900A, and upstream of main filter 60 in filter assembly 2900B. Any of the sampling devices described herein may also comprise flexible screen 2910.

[0451] Flexible screen 2910 is porous, and may comprise, for example, a mesh, netting, a perforated piece of material, or a fabric (e.g., a woven, knit, or knotted material of open texture). Flexible screen 2910 typically comprises a polymer or a metal.

[0452] In filter assembly 2900A, flexible screen 2910 may help open prefilter 2763 after withdrawal and bunching up of prefilter 2763, to help liquid enter prefilter 2763 during bathing of the filters during testing of the filters, for example as described herein with reference to Figs. 3E-I. In filter assembly 2900B, flexible screen 2910 may help open main filter 60 after withdrawal and bunching up of main filter 60, to help liquid enter main filter 60 during bathing of the filter during testing of the filter, for example as described herein with reference to Figs. 3E-I.

[0453] Typically, in filter assembly 2900A, respective surfaces of flexible screen 2910 and prefilter 2763 are not coupled together (although flexible screen 2910 may be coupled to prefilter 2763 at prefilter coupling portion 2804). Typically, in filter assembly 2900B, respective surfaces of flexible screen 2910 and are not coupled together (although flexible screen 2910 may be coupled to main filter 60 at main-filter coupling portion 2802).

[0454] For some applications, an area of flexible screen 2810 equals 5% - 50%, such as 5% - 25%, of an area of main filter 60 and / or of prefilter 2763.

[0455] Reference is now made to Figs. 16A-C, which are schematic cross-sectional illustrations of a sampling device 2220, 2220A and the method of using sampling device 2220, 2220A, in accordance with respective applications of the present invention. Sampling device 2220, 2220A comprises a filtration assembly 2224, 2224A.

[0456] Reference is further made to Figs. 17A-B, which are schematic illustrations of a sampling device 2220, 2220B and a method of using sampling device 2220, 2220B, in accordance with respective applications of the present invention.

[0457] Reference is still further made to Figs. 18A-D, which are schematic cross-sectional illustrations of sampling device 2220, 2220B and the method of using sampling device 2220, 2220B, in accordance with respective applications of the present invention. Sampling device 2220, 2220B comprises a filtration assembly 2224, 2224B.

[0458] Optionally, sampling device 2220, in any of its configurations, implements the features of sampling device 2920, 2920A, 2920B, described hereinbelow with reference to Figs. 19A-C, 20A-C, and 21A-B.

[0459] Other than as described below, sampling device 2220 and filtration assembly 2224 are generally similar to sampling device 2520 and filtration assembly 2524, respectively, described hereinabove with reference to Fig. 6, and like reference numerals refer to like parts; a filter support of sampling device 2220 may or may not implement any of the features of filter support 2662 of sampling device 2520, mutatis mutandis. Alternatively or additionally, the features of sampling device 2220 may be implemented in combination with any of the other sampling devices described herein, mutatis mutandis. Sampling device 2220 comprises source of gas 2204, which is configured to provide gas 2208 into space 2233 defined within filtration assembly 2224, such as outside tubular container 2030 (i.e., not in fluid communication with an interior of tubular container 2030). Filtration assembly 2224 is configured such that providing of gas 2208 into space 2233, when liquid specimen sample 22 is contained in tubular container 2030 and filter 60 is disposed on the support surface, pushes at least a portion of liquid specimen sample 22 through filter 60 and filtrate -pas sage openings 1668 and into waste liquid receptacle 1656.

[0460] Reference is made to Figs. 18A-D. In some configurations, source of gas 2204 may comprise the one or more substances 2205 that generate gas 2208, such as when combined with each other and / or with a liquid, such as liquid of liquid specimen sample 22. In these configurations, source of gas 2204 may optionally implement any of the features thereof described hereinabove with reference to Fig. 6.

[0461] Typically, as gas 2208 is released or generated, the resulting pressure gradually increases during filtration. This increase in pressure helps during the final stages of pushing liquid specimen sample 22 through filter 60, which often require the most pressure, because filter 60 generally becomes progressively more clogged during filtration. By contrast, during earlier stages of filtering, before the filter is particularly clogged, lower pressure is desirable, because using lower pressure results in better filtration. Source of gas 2204 thus appropriately applies lower pressure at the beginning of filtration, and gradually increasing pressure throughout filtration, which corresponds to, and helps address, the gradual increase in clogging of filter 60 during filtration.

[0462] As mentioned above, source of gas 2204 is configured to provide gas 2208 into space 2233 defined within filtration assembly 2224. For some applications, space 2233 is space 2234, described hereinabove with reference to Fig. 6.

[0463] Reference is made to Figs. 16A-C. In this configuration, source of gas 2204 comprises a compressed gas container 2240, which stores a gas 2208. Upon opening of compressed gas container 2240, gas 2208 is released into space 2234. For example, as shown in Figs. 16A-C, plunger support 2258, upon movement (e.g., hinged movement) with respect to container housing 2022, opens compressed gas container 2240, such as via an elongate element 2250. Alternatively, movement of plunger head 1742 within tubular container 2030 opens compressed gas container 2240 (configuration not shown). Reference is made to Figs. 6, 16A-C, 17A-B, and 18A-D, as well as to Figs. 19A- C, 20A-C, 21A-B, described hereinbelow. For some applications, such as shown in these figures, filtration assembly 2224 or filtration assembly 2524 is configured such that movement of plunger head 1742 within tubular container 2030 causes source of gas 2204 to provide gas 2208. Typically, in these configurations, the movement of plunger head 1742 within tubular container 2030 is insufficient to push a meaningful portion of liquid specimen sample 22 through filter 60. For other applications, source of gas 2204 is configured to provide gas 2208 upon manual activation of source of gas 2204, such as described in above-mentioned International Application PCT / IL2024 / 050679, with reference to Figs. 23A-C and 24A-C thereof.

[0464] For some of these applications, the movement of plunger head 1742 within tubular container 2030 causes distal movement of tubular container 2030 within container housing 2022. This distal movement of tubular container 2030 within container housing 2022 may open container 2206 of source of gas 2204. For example, this distal movement of tubular container 2030 may open container 2206 by breaching (e.g., rupturing, penetrating, and / or tearing) container 2206, e.g., by pushing one or more spikes 2242 into a wall of container 2206, as shown in Fig. 18B. Optionally, the one or more spikes 2242 are defined by a distal end of a shaft 2238, and the proximal end of shaft 2238 is pushed distally by distal end 2107 of tubular container 2030. Opening of container 2206 causes a reaction that generates gas 2208, such as described above.

[0465] Reference is made to Figs. 6 and 16A-C. In the configurations shown in these figures, the movement of plunger head 1742 within tubular container 2030 is typically caused by non-rotational insertion of plunger head 1742 into tubular container 2030 with respect to container housing 2022. For example, filtration assembly 2224A or filtration assembly 2524 may further comprise a plunger support 2258, which is coupled to a proximal portion of plunger 1740. Plunger support 2258 may be hingedly attached to container housing 2022 (e.g., by a hinge 2260, labeled in Fig. 16A), typically so as to enable a change in orientation between a central longitudinal axis of plunger 1740 and a central longitudinal axis of container housing 2022. This change in orientation transitions container opening 2036 from an open position to a closed position, in which plunger head 1742 covers container opening 2036. Hinge 2260 may comprise (a) moving components, e.g., may comprise a barrel hinge (such as shown), e.g., comprising two or more knuckles and a pin, or (b) a flexible hinge, e.g., a living hinge (configuration not shown). Reference is made to Figs. 17A-B and 18A-D. In this configuration, the movement of plunger head 1742 within tubular container 2030 is typically caused by rotation of plunger head 1742 with respect to container housing 2022.

[0466] Reference is made to Figs. 6 and 18A-D, as well as to Figs. 20A-C and 21A-B, described hereinbelow. For some applications, such as shown in these figures, the filtration assembly is shaped so as to define gas-release regulation chamber 2232, in which source of gas 2204 is disposed. Gas-release regulation chamber 2232 is nearly entirely isolated from space 2234. Gas-release regulation chamber 2232 is in fluid communication with space 2234 only by one or more narrow openings 2236, e.g., having a total (combined) area of 75 - 8,000 square microns, e.g., if a single circular narrow opening 2236 is provided, it may have a diameter of 10 - 100 microns. The one or more narrow openings 2236 may help provide a controlled flow rate of gas 2208 into space 2234. Optionally, the one or more narrow openings 2236 are defined by shaft 2238 that also defines the one or more spikes 2242 for puncturing container 2206 (labeled in Figs. 18A-B, as well as in Figs. 20B and 21A, described hereinbelow). In the configurations shown in the figures, gas-release regulation chamber 2232 is in fluid communication with space 2234 via exactly one narrow opening 2236.

[0467] For other applications, such as shown in Figs. 15A-D of above-mentioned International Application PCT / IL2024 / 050679, the filtration assembly is not shaped so as to define a gas-release regulation chamber, and source of gas 2204 is instead disposed in space 2234. For example, the one or more substances 2205 may comprise solid substance 2205A, which may comprise a solid, such as a tablet (as shown) or a powder (not shown), disposed at the bottom of space 2234.

[0468] Reference is now made to Figs. 19A-C, which are schematic illustrations of sampling device 2920, 2920A and a method of using sampling device 2920, 2920A, in accordance with respective applications of the present invention.

[0469] Reference is further made to Figs. 20A-C, which are schematic cross-sectional illustrations of sampling device 2920, 2920A and a method of using sampling device 2920, 2920A, in accordance with respective applications of the present invention.

[0470] Reference is still further made to Figs. 21A-B, which are schematic cross-sectional illustrations of a sampling device 2920, 2920B and a method of using sampling device 2920, 2920B, in accordance with respective applications of the present invention. Sampling device 2920 may implement any of the features of the other sampling devices described herein, including, but not limited to sampling device 2520, described with reference to Figs. 6, 7A-C, and 8A-D; sampling device 2820C, described with reference to Figs. 14A-F; and sampling device 2220, 2220A, 2220B, described with reference to Figs. 16A-C, 17A-B, and 18A-D, mutatis mutandis.

[0471] By way of example and not limitation, the configurations of sampling device 2920 shown in Figs. 19A-C, 20A-C, and 21A-B are generally similar to sampling device 2520, described with reference to Fig. 6, other than as described below. However, sampling device 2920 may implement any of the features of any of the other sampling devices described herein, including, but not limited to sampling device 2520, described with reference to Figs. 6, 7A-C, and 8A-D; sampling device 2820C, described with reference to Figs. 14A-F; and sampling device 2220, 2220A, 2220B, described with reference to Figs. 16A-C, 17A-B, and 18A-D, mutatis mutandis. Sampling device 2920 may or may not implement all of the features of sampling device 2520, such as the features of filter support 2662, described hereinabove with reference to Figs. 6, 7A-C, and 8A-D. Like reference numerals refer to like parts.

[0472] Sampling device 2920, 2920A, 2920B comprises a filtration assembly 2924, 2924A, 2924B, respectively, which comprises:

[0473] • filter 60, such as described hereinabove;

[0474] • a container housing 2922, which (a) is shaped so as to define a container-housing pressure-release vent 2970, and (b) comprises lateral wall 2923;

[0475] • tubular container 2030, such as described hereinabove;

[0476] • plunger 1740, such as described hereinabove; and

[0477] • source of gas 2204, such as described hereinabove.

[0478] Such as shown in Figs. 20A-B and 21 A, tubular container 2030 is disposed at least partially within container housing 2922 in a vent-isolation position 2974, such that tubular container 2030 is moveable with respect to container housing 2922 and forms a tubularcontainer fluid-tight movable seal 2976 with an inner surface 2921 of lateral wall 2923 of container housing 2922 (for example, using an O-ring), such that proximal motion of tubular container 2030 with respect to container housing 2922 expands space 2233, 2234 within filtration assembly 2924, 2924A, 2924B between (a) a proximally-facing internal surface 2108 of container housing 2922 and (b) external surface 2106 of tubular container 2030 that is defined by distal end 2107 of tubular container 2030.

[0479] While tubular container 2030 is disposed at least partially within container housing 2922 in vent-isolation position 2974, space 2233, 2234 is fluidly isolated from containerhousing pressure-release vent 2970, such as shown in Figs. 20A-B and 21A.

[0480] Filtration assembly 2924, 2924A, 2924B is configured such that the providing of gas 2208 into space 2233, 2234, when liquid specimen sample 22 is contained in tubular container 2030 and filter 60 is disposed on support surface 1659 (labeled in Fig. 20A):

[0481] • while space 2233, 2234 is fluidly isolated from container-housing pressure-release vent 2970, increases the pressure in space 2233, 2234 so as to proximally move tubular container 2030 with respect to plunger head 1742 during a plunger stroke (it is noted the plunger 1740 may or may not move with respect to container housing 2922 during the plunger stroke; the plunger stroke is caused by relative movement between plunger head 1742 and tubular container 2030), thereby pushing at least a portion of liquid specimen sample 22 through filter 60 and filtrate-passage openings 1668 and into waste liquid receptacle 1656, and

[0482] • upon completion of the plunger stroke, brings space 2233, 2234 into fluid communication with container-housing pressure-release vent 2970, thereby releasing at least a portion of gas 2208 from space 2233, 2234 via container-housing pressure-release vent 2970, such as shown in Figs. 20C and 21B.

[0483] As a result, filtration assembly 2924, 2924A, 2924B is configured, upon completion of the plunger stroke and filtration of liquid specimen sample 22 into waste liquid receptacle 1656, to limit the rate of pressure increase within space 2233, 2234, and / or allow the pressure within space 2233, 2234 to decrease until it reaches equilibrium with the pressure outside filtration assembly 2924, 2924A, 2924B (typically atmospheric pressure). This may prevent overpressurization of space 2233, 2234 in the event that source of gas 2204 continues to provide gas 2208 after completion of the plunger stroke volume. This prevention of overpressurization may contribute to the safety of the filtration assembly.

[0484] For some applications, when tubular container 2030 is disposed at least partially within container housing 2922 in vent-isolation position 2974, such as shown in Figs. 20A- B and 21A, tubular-container fluid-tight movable seal 2976 is disposed distal to containerhousing pressure-release vent 2970, thereby fluidly isolating space 2233, 2234 from container-housing pressure-release vent 2970. Filtration assembly 2924, 2924A, 2924B is configured such that the providing of gas 2208 into space 2233, 2234, when liquid specimen sample 22 is contained in tubular container 2030 and filter 60 is disposed on support surface 1659:

[0485] • while tubular-container fluid-tight movable seal 2976 is disposed distal to containerhousing pressure-release vent 2970, increases the pressure in space 2233, 2234 so as to proximally move tubular container 2030 with respect to plunger head 1742 during the plunger stroke, thereby pushing the at least a portion of liquid specimen sample 22 through filter 60 and filtrate-passage openings 1668 and into waste liquid receptacle 1656, such as shown in Figs. 20B and 21A, and

[0486] • upon completion of the plunger stroke, disposes tubular-container fluid-tight movable seal 2976 at least partially proximal to container-housing pressure-release vent 2970, thereby bringing space 2233, 2234 into fluid communication with container-housing pressure-release vent 2970 and releasing the at least a portion of gas 2208 from space 2233, 2234 via container-housing pressure-release vent 2970, such as shown in Figs. 20C and 21B.

[0487] For some applications, container housing 2922 is shaped so as to define containerhousing pressure-release vent 2970 through lateral wall 2923 of container housing 2922.

[0488] For some applications, container-housing pressure-release vent 2970 is in fluid communication with the atmosphere 2978 outside filtration assembly 2924, 2924A, 2924B.

[0489] As described hereinabove, source of gas 2204 may comprise one or more substances 2205 that generate gas 2208; the techniques described hereinabove may optionally be implemented in sampling device 2920. Alternatively, also as described hereinabove, source of gas 2204 may comprises compressed gas container 2240 containing gas 2208; the techniques described hereinabove may optionally be implemented in sampling device 2920.

[0490] Optionally, source of gas 2204 may be configured to provide gas 2208 upon manual activation of source of gas 2204, such as described hereinabove; the techniques described hereinabove may optionally be implemented in sampling device 2920. Alternatively, filtration assembly 2924, 2924A, 2924B may be configured such that movement of plunger head 1742 within tubular container 2030 causes source of gas 2204 to provide gas 2208, such as described hereinabove; the techniques described hereinabove may optionally be implemented in sampling device 2920. For some applications, filtration assembly 2924, 2924A, 2924B is shaped so as to define gas-release regulation chamber 2232, which is in fluid communication with space 2233, 2234 only by one or more openings 2236, and source of gas 2204 is disposed in fluid communication with gas-release regulation chamber 2232, such as described hereinabove with reference to Figs. 6 and 18A-D; the techniques described hereinabove may optionally be implemented in sampling device 2920.

[0491] In some applications of the present invention, the release of the at least a portion of gas 2208 via container-housing pressure-release vent 2970 actuates a mechanical user indicator 2980. Thus, the actuation of mechanical user indicator 2980 occurs upon conclusion of the plunger stroke and filtration of liquid specimen sample 22 into waste liquid receptacle 1656.

[0492] For some applications, such as in sampling device 2920, 2920A, as shown in Figs. 20A-C, mechanical user indicator 2980 is acoustic. For example, mechanical user indicator 2980 may comprise a whistle 2984, and passage of the released at least a portion of gas 2208 through whistle 2984 blows whistle 2984.

[0493] Alternatively or additionally, for some applications, such as in sampling device 2920, 2920B, as shown in Figs. 21A-B, mechanical user indicator 2980 is visual. For example, mechanical user indicator 2980 may comprise a flag 2988. As used in the present application, including in the claims and Inventive Concepts, “flag” means something used like a flag to signal or attract attention. For example, flag 2988 may be shaped as a peg or a rod, such as shown. The portion of gas 2208 released via container-housing pressurerelease vent 2970 may move the flag, such as shown. Alternatively, mechanical user indicator 2980 may comprise a balloon that is inflated by the at least a portion of gas 2208 that is released via container-housing pres sure -release vent 2970 (configuration not shown). Further alternatively, mechanical user indicator 2980 may be configured to change color, such as by the sliding of colored element, upon the release of the at least a portion of gas 2208 via container-housing pressure -release vent 2970 (configuration not shown).

[0494] Optionally, mechanical user indicator 2980 is both acoustic and visual (configuration not shown).

[0495] For some applications, filtration assembly 2924, 2924A, 2924B further comprises pressure-responsive valve 2552, which is configured to limit a pressure within space 2233, 2234 even while space 2233, 2234 is fluidly isolated from container-housing pressure- release vent 2970, such as described hereinabove with reference to Fig. 6. For some of these applications, pressure-responsive valve 2552 is configured to limit the pressure in space 2233, 2234 by blocking flow of gas 2208 into space 2233, 2234 responsively to the pressure in space 2233, 2234. For others of these applications, pressure-responsive valve 2552 comprises pressure relief valve 2556, which is configured to release a portion of gas 2208 from space 2233, 2234 when the pressure within space 2233, 2234 exceeds a threshold pressure even while space 2233, 2234 is fluidly isolated from container-housing pressurerelease vent 2970, such as described hereinabove with reference to Fig. 6; optionally, pressure relief valve 2556 is located so as to release the portion of gas 2208 from space 2233, 2234 to the atmosphere 2978 outside filtration assembly 2924, 2924A, 2924B when the pressure within space 2233, 2234 exceeds the threshold pressure, such as described hereinabove with reference to Fig. 6.

[0496] Reference is again made to Figs. 19A-C, 20A-C, and 21A-B. For some applications, a method for concentrating liquid specimen sample 22 is provided, the method comprising:

[0497] • placing, via proximal container opening 2036, liquid specimen sample 22 in tubular container 2030 of filtration assembly 2924, 2924A, 2924B of sampling device 2220, 2220A, 2220B, while tubular container 2030 is disposed at least partially within container housing 2022 in vent-isolation position 2974, such that tubular container 2030 is moveable with respect to container housing 2922 and forms tubularcontainer fluid-tight movable seal 2976 with inner surface 2921 of lateral wall 2923 of container housing 2922, such that proximal motion of tubular container 2030 with respect to container housing 2922 expands space 2233, 2234 within filtration assembly 2924, 2924A, 2924B between (a) proximally-facing internal surface 2108 of container housing 2922 and (b) external surface 2106 of tubular container 2030 that is defined by distal end 2107 of tubular container 2030, space 2233, 2234 fluidly isolated from container-housing pres sure -release vent 2970 defined by container housing 2922;

[0498] • inserting plunger head 1742 of plunger 1740 into tubular container 2030 via proximal container opening 2036 of tubular container 2030, such that the lateral surface of plunger head 1742 forms a plunger-head fluid-tight movable seal with an inner wall of tubular container 2030;

[0499] • causing source of gas 2204 of filtration assembly 2924, 2924A, 2924B to provide gas into space 2233, 2234, so as to:

[0500] ■ while space 2233, 2234 is fluidly isolated from container-housing pressurerelease vent 2970, increase the pressure in space 2233, 2234 so as to proximally move tubular container 2030 with respect to plunger head 1742 during a plunger stroke, thereby pushing at least a portion of liquid specimen sample 22 through filter 60 and filtrate-passage openings 1668 and into waste liquid receptacle 1656, and

[0501] ■ upon completion of the plunger stroke, bring space 2233, 2234 into fluid communication with container-housing pres sure -release vent 2970, thereby releasing at least a portion of gas 2208 from space 2233, 2234 via containerhousing pressure-release vent 2970.

[0502] For some applications, causing source of gas 2204 to provide gas 2208 comprises manually activating source of gas 2204. For other applications, causing source of gas 2204 to provide gas 2208 comprises moving plunger head 1742 within tubular container 2030.

[0503] For some applications, the release of the at least a portion of gas 2208 via containerhousing pressure-release vent 2970 actuates mechanical user indicator 2980, such as described hereinabove.

[0504] For some applications, the method further comprises detecting the presence of a biological particulate trapped by filter 60, such as using the techniques described hereinabove with reference to Figs. 1A-4 and / or the techniques described in the patent application publications incorporated hereinbelow by reference.

[0505] Reference is again made to Fig. 19A-C, 20A-C, and 21A-B. In some applications of the present invention, filtration assembly 2924, 2924A, 2924B further comprises a visual indicator flag 3000, which may, for example, be shaped as a tab, peg, or rod. Filtration assembly 2924 is configured such that visual indicator flag 3000 is:

[0506] • in a pre-filtration base state prior to the beginning of the plunger stroke of plunger 1740 (and thus is typically at least partially obscured (typically mostly obscured) by filtration assembly 2924, 2924A, 2924B), such as shown in Figs. 19A-B and 20A, and

[0507] • in a post-filtration completion stage upon completion of the plunger stroke and filtration of liquid specimen sample 22 into waste liquid receptacle 1656 (and thus exposed by filtration assembly 2924, 2924A, 2924B), such as shown in Figs. 19C, 20C, 21B.

[0508] (Visual indicator flag 3000 may also assume intermediary states during the plunger stroke, such as shown in Figs. 20B and 21 A.)

[0509] For some applications, proximal movement of tubular container 2030 with respect to plunger head 1742 during the plunger stroke proximally pushes visual indicator flag 3000, thereby transitioning visual indicator flag 3000 from the pre-filtration base state, such as shown in Figs. 19A-B and 20A, to the post-filtration completion state, such as shown in Figs. 19C, 20C, and 21B.

[0510] For some applications, a proximal cap 3002 of filtration assembly 2924, 2924A, 2924B is shaped so as to define an opening 3004, such as a slot, through which visual indicator flag 3000 moves during the proximal movement of visual indicator flag 3000.

[0511] Optionally, visual indicator flag 3000 is shaped so as to define a detent 3006, and filtration assembly 2924, 2924A, 2924B, e.g., an outer lateral surface of plunger 1740, is shaped so as to define a corresponding indentation 3008. Detent 3006 is shaped and positioned to engage indentation 3008 when visual indicator flag 3000 is in the pre-filtration base state, so as to prevent inadvertent proximal movement visual indicator flag 3000 prior to the plunger stroke, such as if the user turns over the filtration assembly prior to filtration.

[0512] Optionally, filtration assembly 2924, 2924A, 2924B comprises a plurality of visual indicator flags 3000, e.g., two visual indicator flags 3000, such as shown.

[0513] Visual indicator flags 3000 may implemented in combination with mechanical user indicator 2980 or without mechanical user indicator 2980.

[0514] For some applications, the techniques described herein are implemented in combination with kit 1000 and / or testing kit 1100, described in above-mentioned PCT Publication WO 2023 / 131948 with reference to Fig. 30 and Fig. 31 thereof, respectively, mutatis mutandis.

[0515] In an embodiment, the techniques and apparatus described herein are combined with techniques and apparatus described in one or more of the following patent applications, which are assigned to the assignee of the present application and are incorporated herein by reference:

[0516] • US Patent Application Publication 2019 / 0381498 to Fruchter et al.; • US Provisional Application 62 / 727,268, filed September 5, 2018;

[0517] • PCT Publication WO 2020 / 049566 to Fruchter et al.;

[0518] • US Patent Application Publication 2021 / 0215585 to Fruchter et al.;

[0519] • US Provisional Application 62 / 988,145, filed March 11, 2020;

[0520] • US Provisional Application 62 / 988,259, filed March 11, 2020;

[0521] • US Provisional Applications 63 / 020,723, filed May 6, 2020; 63 / 037,707, filed June 11, 2020; 63 / 067,535, filed August 19, 2020; 63 / 117,294, filed November 23, 2020; 63 / 156,843, filed March 4, 2021; 63 / 158,005, filed March 8, 2021; 63 / 166,378, filed March 26, 2021; and 63 / 176,565, filed April 19, 2021;

[0522] • US Provisional Application 63 / 071,529, filed August 28, 2020;

[0523] • PCT Publication WO 2021 / 044417 to Holtz et al. ;

[0524] • US Patent Application Publication 2021 / 0102876 to Fruchter et al.;

[0525] • PCT Publication WO 2021 / 181338 to Fruchter et al., and US Patent Application Publication 2023 / 0098151 in the US national stage thereof;

[0526] • PCT Publication WO 2021 / 181339 to Feldman et al., and US Patent Application Publication 2023 / 0096409 in the US national stage thereof;

[0527] • PCT Publication WO 2021 / 224925 to Levitz et al., and US Application 17 / 921,672 in the national stage thereof, which published as US Patent Application Publication 2023 / 0165570 to Levitz et al.;

[0528] • PCT Publication WO 2022 / 044002 to Levitz et al., and US Application 18 / 023,607 in the national stage thereof, which published as US Patent Application Publication 2024 / 0100452 to Levitz et al.;

[0529] • US Provisional Application 63 / 134,282, filed January 6, 2021;

[0530] • PCT Publication WO 2022 / 149135 to Feldman et al.;

[0531] • US Provisional Application 63 / 388,851, filed July 13, 2022, and US Provisional Application 63 / 432,231, filed December 13, 2022;

[0532] • US Patent Application Publication 2023 / 0061094 to Levitz et al.;

[0533] • US Patent Application Publication 2023 / 0152192 to Feldman et al.; PCT Publication WO 2023 / 095146 to Levitz et al;

[0534] • PCT Publication WO 2023 / 131948 to Levitz et al., and US Application 18 / 763,483 in the national stage thereof, which published as US Patent Application Publication 2024 / 0361216 to Levitz et al.; • PCT Publication WO 2024 / 013747 to Feldman et al.;

[0535] • US Patent Application Publication 2023 / 0400459 to Levitz;

[0536] • US Provisional Application 63 / 621,875, filed January 17, 2024;

[0537] • US Provisional Application 63 / 556,042, filed February 21, 2024; and

[0538] • International Application PCT / IL2024 / 050679, filed July 11, 2024. In an embodiment, the techniques and apparatus described herein are combined with techniques and apparatus described in PCT Publication WO 2022 / 149135 to Feldman et al., with reference to Figs. 1A-35B thereof.

[0539] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.

Claims

CLAIMS1. A sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises:(i) a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample;(ii) a plunger, which (a) comprises a plunger head and a plunger rod, which has a distal end portion to which the plunger head is coupled, and (b) is insertable into the tubular container via the proximal container opening, such that a lateral surface of the plunger head forms a fluid-tight movable seal with the inner wall of the tubular container;(iii) a waste liquid receptacle;(iv) a filter support, which comprises:(a) a rigid solid base, which includes (1) a first portion, which is shaped so as to define a plurality of filtrate -passage openings through the rigid solid base into the waste liquid receptacle, and (2) a second portion, which is shaped so as to define a pres sure -release opening through the rigid solid base into the waste liquid receptacle; and(b) a fluid-permeable layer, fixed to the rigid solid base covering the first portion without covering the second portion, wherein the fluid-permeable layer and the second portion of the rigid solid base together are shaped so as to define a support surface; and(v) a filter, which is removably disposed on the support surface, wherein the filtration assembly is configured such that: pressurizing the liquid specimen sample in the tubular container at a first pressure less than a threshold pressure pushes a first portion of the liquid specimen sample (a) through the filter, (b) (1) partially through the fluid -permeable layer and the filtrate-passage openings and (2) partially through the pressure-release opening, and (c) into the waste liquid receptacle, and pressurizing the liquid specimen sample in the tubular container at a second pressure greater than the threshold pressure (i) perforates a portion of the filter covering the pressure -release opening and (ii) pushes a second portion of the liquid specimen sample through the perforated portion of the filter and the pressure -release opening, and into the waste liquid receptacle.

2. The sampling device according to claim 1, wherein the fluid-permeable layer comprises a non-woven fabric, a woven fabric, or a mesh.

3. The sampling device according to claim 1, wherein the fluid-permeable layer has a porosity greater than a porosity of the filter.

4. The sampling device according to claim 1, wherein the pressure-release opening has a cross-sectional area greater than an average cross-sectional area of the filtrate -passage openings.

5. The sampling device according to claim 1, wherein the first portion of the rigid solid base is shaped so as to define at least 5 filtrate -passage openings.

6. The sampling device according to claim 5, wherein the first portion of the rigid solid base is shaped so as to define 5 - 1,000 filtrate-passage openings.

7. The sampling device according to claim 1, wherein respective portions of the support surface defined by the fluid-permeable layer and the second portion of the rigid solid base are flush with each other.

8. The sampling device according to claim 1, wherein the rigid solid base is shaped so as to define no more than five pressure-release openings through the rigid solid base into the waste liquid receptacle.

9. The sampling device according to claim 8, wherein the rigid solid base is shaped so as to define exactly one pressure-release opening through the rigid solid base into the waste liquid receptacle.

10. The sampling device according to any one of claims 1-9, wherein the filtration assembly further comprises a dissolvable plug disposed in the pressure-release opening, wherein the dissolvable plug comprises a material that is configured to dissolve upon exposure to the liquid specimen sample, via the filter, for at least a threshold amount of time after commencement of exposure to the liquid specimen sample, and wherein, prior to dissolving of the material, the dissolvable plug prevents passage of the liquid specimen sample through the pressure -release opening even when the liquid specimen sample is pressured at the second pressure, and thereby prevents perforation of the portion of the filter covering the pressure-release opening.

11. The sampling device according to claim 10, wherein the threshold amount of time is 30 - 300 seconds.

12. The sampling device according to claim 10, wherein the pressure-release opening narrows at a downstream end portion thereof, in order to prevent the pressure applied to the dissolvable plug by the liquid specimen sample, via the filter, from ejecting the dissolvable plug from the downstream end portion prior to the dissolving of the dissolvable material.

13. The sampling device according to any one of claims 1-9, wherein the plunger rod is shaped so as to define the waste liquid receptacle within the plunger rod, and wherein the plunger head comprises the filter support.

14. The sampling device according to claim 13, wherein the sampling device further comprises a container housing, and wherein the tubular container is disposed at least partially within the container housing, such that the tubular container is moveable with respect to the container housing and the plunger head.

15. The sampling device according to claim 14, wherein the sampling device further includes a source of gas, which is configured to provide gas into a space by releasing or generating the gas, the space defined between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, and wherein the filtration assembly is configured such that providing the gas into the space increases pressure in the space, thereby proximally moving the tubular container with respect to the plunger head.

16. The sampling device according to any one of claims 1-9, wherein an internal distal bottom surface of the tubular container comprises the filter support.

17. A method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device; inserting a plunger into the tubular container via the proximal container opening, such that a lateral surface of a plunger head of the plunger forms a fluid-tight movable seal with an inner wall of the tubular container, wherein the plunger further includes a plunger rod, which has a distal end portion to which the plunger head is coupled; andpressurizing the liquid specimen sample in the tubular container, wherein the filtration assembly further includes a filter support, which includes: a rigid solid base, which includes (i) a first portion, which is shaped as to define a plurality of filtrate-passage openings through the rigid solid base into a waste liquid receptacle of the filtration assembly, and (ii) a second portion, which is shaped so as to define a pressure-release opening through the rigid solid base into the waste liquid receptacle; and a fluid-permeable layer, fixed to the rigid solid base covering the first portion without covering the second portion, wherein the fluid-permeable layer and the second portion of the rigid solid base together are shaped so as to define a support surface, wherein a filter is removably disposed on the support surface, and wherein the filtration assembly is configured such that: pressurizing the liquid specimen sample in the tubular container at a first pressure less than a threshold pressure pushes a first portion of the liquid specimen sample (a) through the filter, (b) (1) partially through the fluid -permeable layer and the filtrate-passage openings and (2) partially through the pressure-release opening, and (c) into the waste liquid receptacle, and pressurizing the liquid specimen sample in the tubular container at a second pressure greater than the threshold pressure (i) perforates a portion of the filter covering the pressure -release opening and (ii) pushes a second portion of the liquid specimen sample through the perforated portion of the filter and the pressure -release opening, and into the waste liquid receptacle.

18. The method according to claim 17, wherein the fluid-permeable layer includes a non-woven fabric, a woven fabric, or a mesh.

19. The method according to claim 17, wherein the fluid-permeable layer has a porosity greater than a porosity of the filter.

20. The method according to claim 17, wherein the pressure-release opening has a cross-sectional area greater than an average cross-sectional area of the filtrate -pas sage openings.

21. The method according to claim 17, wherein the first portion of the rigid solid base is shaped so as to define at least 5 filtrate -pas sage openings.

22. The method according to claim 21, wherein the first portion of the rigid solid base is shaped so as to define 5 -1,000 filtrate-passage openings.

23. The method according to claim 17, wherein respective portions of the support surface defined by the fluid-permeable layer and the second portion of the rigid solid base are flush with each other.

24. The method according to claim 17, wherein the rigid solid base is shaped so as to define no more than five pres sure -release openings through the rigid solid base into the waste liquid receptacle.

25. The method according to claim 24, wherein the rigid solid base is shaped so as to define exactly one pressure -release opening through the rigid solid base into the waste liquid receptacle.

26. The method according to any one of claims 17-25, wherein the filtration assembly further includes a dissolvable plug disposed in the pressure-release opening, wherein the dissolvable plug includes a material that is configured to dissolve upon exposure to the liquid specimen sample, via the filter, for at least a threshold amount of time after commencement of exposure to the liquid specimen sample, and wherein, prior to dissolving of the material, the dissolvable plug prevents passage of the liquid specimen sample through the pressure -release opening even when the liquid specimen sample is pressured at the second pressure, and thereby prevents perforation of the portion of the filter covering the pressure-release opening.

27. The method according to claim 26, wherein the threshold amount of time is 30 - 300 seconds.

28. The method according to claim 26, wherein the pressure-release opening narrows at a downstream end portion thereof, in order to prevent the pressure applied to the dissolvable plug by the liquid specimen sample, via the filter, from ejecting the dissolvable plug from the downstream end portion prior to the dissolving of the dissolvable material.

29. The method according to any one of claims 17-25, wherein the plunger rod is shaped so as to define the waste liquid receptacle within the plunger rod, and wherein the plunger head includes the filter support.

30. The method according to claim 29, wherein the sampling device further includes a container housing, wherein the tubular container is disposed at least partially within the container housing, such that the tubular container is moveable with respect to the container housing and the plunger head, and wherein pressurizing the liquid specimen sample in the tubular container comprises proximally moving the tubular container with respect to the plunger head.

31. The method according to claim 30, wherein the sampling device further includes a source of gas, which is configured to provide gas into a space by releasing or generating the gas, the space defined between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, and wherein proximally moving the tubular container with respect to the plunger head comprises causing the source of gas to provide the gas into the space to as to increases pressure in the space.

32. The method according to any one of claims 17-25, wherein an internal distal bottom surface of the tubular container includes the filter support.

33. A sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer comprising a main-filter-withdrawal shaft, which is directly or indirectly coupled to the main filter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the main-filter- withdrawal shaft out of the filtration assembly pulls the main filter from the filtrationassembly, while leaving the prefilter within the filtration assembly.

34. The sampling device according to claim 33, wherein the filtration assembly comprises a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate-passage openings through the prefilter support, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

35. The sampling device according to any one of claims 33-34, wherein the filtration assembly is shaped so as to define therewithin a waste liquid receptacle, wherein the filtration assembly comprises a main filter support, which is shaped so as to define (a) a main distal support surface, and (b) a plurality of main filtrate -pas sage openings through the main filter support into the waste liquid receptacle, wherein the main filter is removably disposed on the main distal support surface of the main filter support, and wherein the pressure source is configured, when the liquid specimen sample is contained in the tubular container and the main filter is removably disposed on the main distal support surface of the main filter support in the tubular container, to push the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

36. The sampling device according to claim 33, wherein the sampling device further comprises a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

37. The sampling device according to claim 36, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle via the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

38. The sampling device according to claim 37,wherein the sampling device further comprises a shaft, and wherein the sampling device is configured such that that a distal portion of the shaft is axially movable through the receptacle opening so as to advance the main filter into the main-filter-collection receptacle via the receptacle opening.

39. The sampling device according to claim 36, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly by distal movement of the main-filter-collection receptacle with respect to the tubular container.

40. The sampling device according to any one of claims 33-39, wherein the pressure source comprises a plunger, which comprises a plunger head and a plunger rod, and which is insertable into the tubular container via the proximal container opening, and wherein the filtration assembly is configured such that movement of the plunger head within the tubular container, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample through the prefilter and the main filter.

41. The sampling device according to claim 40, wherein the plunger rod (1) has a distal end portion to which the plunger head is coupled, and (2) is shaped so as to define an internal plunger space having a plunger-space proximal opening through a proximal end of the plunger rod, wherein the plunger head is shaped so as to define a plunger-head opening through the plunger head and into the internal plunger space, wherein the main filter is removably disposed on a distal end of the plunger head, wherein the prefilter is fixed to the plunger head distal to the main filter, wherein the main-filter-withdrawal shaft is disposed passing through the internal plunger space, wherein insertion of the plunger into the tubular container via the proximal container opening inserts the main filter and the prefilter into the tubular container and forms a fluid- tight movable seal between a lateral surface of the plunger head and an inner wall of the tubular container, wherein the filtration assembly is configured such that the movement of the plunger head within the tubular container, when the liquid specimen sample is contained in thetubular container and the main filter is removably disposed on the distal end of the plunger head in the tubular container, pushes at least a portion of the liquid specimen sample through the prefilter and the main filter, and wherein the sampling device is configured such that while the plunger head is within the tubular container: the proximal withdrawal of the main-filter-withdrawal shaft out of the internal plunger space pulls the main filter into the internal plunger space via the plunger-head opening and out of the internal plunger space via the plunger-space proximal opening, and removes the main-filter- withdrawal shaft and the main filter from the filtration assembly, while leaving the prefilter fixed to the plunger head.

42. The sampling device according to claim 41, wherein the plunger head is shaped so as to define a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtratepassage openings through the prefilter support, wherein the prefilter support is disposed distal to the main filter, and wherein the prefilter is disposed on the prefilter distal support surface of the prefilter support.

43. The sampling device according to any one of claims 41-42, wherein the plunger rod is shaped so as to define therewithin a waste liquid receptacle, wherein the plunger head is shaped so as to define a main filter support, which is shaped so as to define (a) a main distal support surface, (b) a plurality of main filtratepassage openings through the main filter support into the waste liquid receptacle, and (c) the plunger-head opening, wherein the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head, and wherein the filtration assembly is configured such that when the liquid specimen sample is contained in the tubular container, the plunger head is within the tubular container, and the main filter is removably disposed on the main distal support surface of the main filter support of the plunger head in the tubular container: the movement of the plunger head within the tubular container pushes the at least a portion of the liquid specimen sample through the prefilter, the main filter, and the main filtrate-passage openings and into the waste liquid receptacle.

44. The sampling device according to claim 41, wherein the sampling device further comprises a main-filter-collection receptacle, which is disengageably coupled to the filtration assembly, and wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the main-filter-collection receptacle is disengageably coupled to the filtration assembly.

45. The sampling device according to claim 44, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly while the plunger head is within the tubular container.

46. The sampling device according to claim 44, wherein the main-filter-collection receptacle is removably disposed at least partially within the internal plunger space.

47. The sampling device according to claim 46, wherein the sampling device is configured such that the main-filter-collection receptacle is decouplable from the filtration assembly while the plunger head is within the tubular container.

48. The sampling device according to claim 46, wherein the main-filter-collection receptacle is shaped so as to define a receptacle opening and a shaft-passage hole at an end of the main-filter-collection receptacle opposite the receptacle opening, wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle via the plunger-head opening and the receptacle opening while the main-filter-collection receptacle is disengageably coupled to the filtration assembly, wherein the main-filter-withdrawal shaft (a) is disposed partially within the main- filter-collection receptacle within the internal plunger space, (b) includes a proximal portion that is slidably disposed passing through the shaft -passage hole, and (c) includes the distal portion that passes through the receptacle opening and is directly or indirectly coupled to the main filter, and wherein the sampling device is configured such that proximal withdrawal of the main-filter- withdrawal shaft, while the plunger head is within the tubular container, pulls the main filter into the main-filter-collection receptacle via the plunger-head opening and the receptacle opening.

49. The sampling device according to claim 48, wherein the sampling device is configured such that further proximal withdrawal of the main-filter-withdrawal shaft out of the internal plunger space, while the plunger head is within the tubular container, pulls the main-filter-collection receptacle out of the internal plunger space via the plunger-space proximal opening.

50. The sampling device according to claim 48, further comprising a seal that inhibits fluid leakage between the proximal portion of the main-filter-withdrawal shaft and the shaft-passage hole.

51. The sampling device according to claim 44, wherein the main-filter-collection receptacle is positioned proximal to the plunger head, and wherein the sampling device is configured such that the movement of the plunger head and the main-filter-collection receptacle within the tubular container advances the main filter into the filter-collection receptacle via the plunger-head opening.

52. The sampling device according to claim 51, wherein the sampling device is configured such that the movement of the plunger head and the filter-collection receptacle within the tubular container advances the main filter into the filter-collection receptacle via the plunger-head opening while the main filter remains stationary with respect to a distal end of the tubular container.

53. The sampling device according to claim 51, wherein the filter-collection receptacle is shaped so as to define a receptacle opening, and wherein the sampling device is configured such that the main filter is advanceable into the filter-collection receptacle via the receptacle opening while the filtercollection receptacle is disengageably coupled to the filtration assembly, and wherein the filter-collection receptacle is positioned proximal to the plunger head such that the receptacle opening is in fluid communication with the plunger-head opening.

54. The sampling device according to claim 44, wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the plunger head is within the tubular container.

55. The sampling device according to claim 54, wherein the sampling device is configured such that the main filter is advanceable into the main-filter-collection receptacle while the plunger head is advanced as far as possible within the tubular container.

56. The sampling device according to claim 33, wherein the pressure source comprises a source of gas, configured to provide gas into a space defined within the filtration assembly, and wherein the filtration assembly is configured such that providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, pushes the at least a portion of the liquid specimen sample through the prefilter and the main filter.

57. A testing kit comprising the sampling device according to claim 33, the testing kit further comprising a lateral flow immunoassay test strip, which is configured to detect a presence of a biological particulate trapped by the main filter.

58. The testing kit according to claim 57, further comprising reagents for use with the lateral flow immunoassay test strip.

59. The testing kit according to claim 58, further comprising an extraction tube, into which the main filter is insertable for bathing in the reagents.

60. The testing kit according to claim 57, wherein the biological particulate is selected from the group consisting of: a virus, a bacterium, a microorganism, a fungus, a spore, a mite, a biological cell, a biological antigen, a protein, a protein antigen, and a carbohydrate antigen.

61. The sampling device according to claim 33, wherein the sampling device is configured to bunch up at least a portion of the main filter during removal of the main filter from the tubular container.

62. The sampling device according to claim 61, wherein the sampling device is configured to bunch up the at least a portion of the main filter into a flower-like arrangement during the removal of the main filter from the tubular container.

63. A method for concentrating a liquid specimen sample, the method comprising: placing the liquid specimen sample in a tubular container of a filtration assembly of a sampling device; when the liquid specimen sample is contained in the tubular container and a main filter is in fluid communication with the liquid specimen sample via a prefilter disposed upstream of the main filter in fluid communication with the main filter, activating a pressure source to push at least a portion of the liquid specimen sample downstream through theprefilter and the main filter; and withdrawing a main-filter-withdrawal shaft of a withdrawer out of the filtration assembly, so as to pull the main filter from the filtration assembly, while leaving the prefilter within the filtration assembly, wherein the main-filter- withdrawal shaft is directly or indirectly coupled to the main filter.

64. A sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly: pulls the main filter and the prefilter from the filtration assembly, and bunches up at least respective portions of the main filter and the prefilter, such that at least a part of the bunched-up portion of the prefilter is disposed outside the main filter.

65. A method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, wherein the filtration assembly further includes a main filter; a prefilter, which is disposed upstream of the main filter in fluid communication with the main filter; a withdrawer including one or more filterwithdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source; when the liquid specimen sample is contained in the tubular container and the mainfilter is in fluid communication with the liquid specimen sample via the prefilter, activating the pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter; and withdrawing the one or more filter-withdrawal shafts out of the filtration assembly so as to: pull the main filter and the prefilter from the filtration assembly, and bunch up at least respective portions of the main filter and the prefilter, such that at least a part of the bunched-up portion of the prefilter is disposed outside the main filter.

66. A sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises: a tubular container, which is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample; a main filter; a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support; a prefilter, which is disposed on the prefilter distal support surface of the prefilter support, upstream of the main filter in fluid communication with the main filter via the plurality of prefilter filtrate -pas sage openings; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source, which is configured, when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter, wherein the sampling device is configured such that withdrawal of the one or more filter-withdrawal shafts out of the filtration assembly pulls the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

67. A method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, wherein the filtration assemblyfurther includes a main filter; a prefilter support, which is shaped so as to define a prefilter distal support surface and a plurality of prefilter filtrate -passage openings through the prefilter support; a prefilter, which is disposed on the prefilter distal support surface of the prefilter support, upstream of the main filter in fluid communication with the main filter via the plurality of prefilter filtrate -pas sage openings; a withdrawer comprising one or more filter-withdrawal shafts, which are disposed along an axis of the withdrawer, and are coupled to the main filter and the prefilter; and a pressure source; when the liquid specimen sample is contained in the tubular container and the main filter is in fluid communication with the liquid specimen sample via the prefilter, activating the pressure source to push at least a portion of the liquid specimen sample downstream through the prefilter and the main filter; and withdrawing the one or more filter-withdrawal shafts out of the filtration assembly so as to pull the main filter and the prefilter from the filtration assembly, while leaving the prefilter support within the filtration assembly.

68. A sampling device for concentrating a liquid specimen sample, the sampling device comprising a filtration assembly, which comprises:(i) a filter;(ii) a container housing, which (a) is shaped so as to define a container-housing pressure-release vent, and (b) comprises a lateral wall;(iii) a tubular container, which: is shaped so as to define an inner wall and a proximal container opening for receiving the liquid specimen sample, and is disposed at least partially within the container housing in a vent-isolation position, such that the tubular container is moveable with respect to the container housing and forms a tubular-container fluid-tight movable seal with an inner surface of the lateral wall of the container housing, such that proximal motion of the tubular container with respect to the container housing expands a space within the filtration assembly between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, the space fluidly isolated from the container-housing pressurerelease vent;(iv) a plunger, which comprises: a plunger rod, which is shaped so as to define a waste liquid receptacle; anda plunger head, which (a) is coupled to a distal end portion of the plunger rod, and (b) and comprises a filter support, which is shaped so as to define (a) a support surface on which the filter is removably disposed, and (b) a plurality of filtrate-passage openings through the filter support into the waste liquid receptacle, wherein the plunger is insertable into the tubular container via the proximal container opening, such that a lateral surface of the plunger head forms a plungerhead fluid-tight movable seal with the inner wall of the tubular container; and (v) a source of gas, configured to provide gas into the space, wherein the filtration assembly is configured such that the providing of the gas into the space, when the liquid specimen sample is contained in the tubular container and the filter is disposed on the support surface: while the space is fluidly isolated from the container-housing pressurerelease vent, increases the pressure in the space so as to proximally move the tubular container with respect to the plunger head during a plunger stroke, thereby pushing at least a portion of the liquid specimen sample through the filter and the filtratepassage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, brings the space into fluid communication with the container-housing pressure-release vent, thereby releasing at least a portion of the gas from the space via the container-housing pressure-release vent.

69. A method for concentrating a liquid specimen sample, the method comprising: placing, via a proximal container opening, the liquid specimen sample in a tubular container of a filtration assembly of a sampling device, while the tubular container is disposed at least partially within a container housing of the filtration assembly in a ventisolation position, such that the tubular container is moveable with respect to the container housing and forms a tubular-container fluid-tight movable seal with an inner surface of a lateral wall of the container housing, such that proximal motion of the tubular container with respect to the container housing expands a space within the filtration assembly between (a) a proximally-facing internal surface of the container housing and (b) an external surface of the tubular container that is defined by a distal end of the tubular container, the space fluidly isolated from a container-housing pressure-release vent defined by the container housing;inserting a plunger head of a plunger of the filtration assembly into the tubular container via the proximal container opening of the tubular container, such that a lateral surface of the plunger head forms a plunger-head fluid-tight movable seal with an inner wall of the tubular container, wherein the plunger further includes a plunger rod, which (a) has a distal end portion to which the plunger head is coupled, and (b) is shaped so as to define a waste liquid receptacle within the plunger rod, wherein the plunger head includes a filter support, which is shaped so as to define (a) a support surface on which a filter is removably disposed, and (b) a plurality of filtrate -passage openings through the filter support into the waste liquid receptacle; and causing a source of gas of the filtration assembly to provide gas into the space, so as to: while the space is fluidly isolated from the container-housing pressurerelease vent, increase the pressure in the space so as to proximally move the tubular container with respect to the plunger head during a plunger stroke, thereby pushing at least a portion of the liquid specimen sample through the filter and the filtratepassage openings and into the waste liquid receptacle, and upon completion of the plunger stroke, bring the space into fluid communication with the container-housing pressure-release vent, thereby releasing at least a portion of the gas from the space via the container-housing pressure-release vent.

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