Cap with ventilation plug for biological fluid sampling device

Abstract

To provide a cap with a ventilation plug for a biological fluid sampling device.SOLUTION: A ventilation plug allows air to pass through, and prevents a blood sample from passing through. In one embodiment, the ventilation plug is a porous plug. In one embodiment, a cap comprises a ventilation plug that comprises a carboxymethylcellulose additive. Also, disclosed is a cap that limits analyte bias due to interaction of plasma blood ions with carboxymethyl cellulose by reducing a contact area between the blood and the carboxymethylcellulose additive, for example, by reducing a radius.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This application claims priority to U.S. Provisional Application No. 62 / 665,092, entitled "Cap with Vent Plug for Biological Fluid Collection Device," filed May 1, 2018, the disclosure of which is incorporated herein by reference in its entirety.

[0002] FIELD OF THE DISCLOSURE The present disclosure relates generally to biological fluid collection devices, and more particularly to a cap with a vent plug for a biological fluid collection device. [Background technology]

[0003] A cap is required to seal the collection chamber of a biological fluid collection device. The collection chamber must be evacuated before sealing the liquid within the chamber. One of the primary uses of the cap is to seal the biological fluid collection device after removing any residual air from the system. This has two major impacts on sample collection. First, blood gas measurements must be performed using blood that is collected anaerobically (in air-free conditions). Second, removing the air facilitates collection of the entire available sample volume, rather than just a portion of it due to the presence of air pockets. Both of these impacts are important for obtaining a properly anticoagulated, unbiased blood sample. Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a cap with a vent plug for a biological fluid collection device, the vent plug allowing the passage of air but preventing the passage of a blood sample. [Means for solving the problem]

[0005] In one embodiment, the vent plug is a porous plug. In one embodiment, the cap includes a vent plug that includes a carboxymethyl cellulose additive.

[0006] In one embodiment, the present disclosure provides a cap that limits analyte bias due to plasma ion interaction with carboxymethylcellulose by reducing the contact area between the blood and the carboxymethylcellulose additive, e.g., by reducing the radius. In one embodiment, the present disclosure provides a cap that limits analyte bias due to plasma ion interaction with carboxymethylcellulose by increasing the path length between the blood and the carboxymethylcellulose additive, e.g., by increasing the path length. In one embodiment, the present disclosure provides a cap that limits analyte bias due to plasma ion interaction with carboxymethylcellulose by introducing a porous material in front of the carboxymethylcellulose additive plug to reduce the diffusivity.

[0007] A cap for a biological fluid collection device according to an embodiment of the present invention includes a cap body defining a first chamber having a first diameter, a second chamber having a second diameter, and a third chamber having a third diameter, the second chamber being between the first and third chambers; and a vent plug disposed in the third chamber, the vent plug including a carboxymethyl cellulose additive, wherein the second diameter is smaller than the first diameter and the second diameter is smaller than the third diameter.

[0008] In one configuration, the vent plug allows air to pass through while preventing a blood sample from passing through. In another configuration, the vent plug is a porous plug. In yet another configuration, the first diameter is smaller than the third diameter. In one configuration, the first diameter is 1.016 mm, the second diameter is 0.4 mm, and the third diameter is 1.5 mm. In another configuration, the length of the second chamber is 1.6 mm and the length of the third chamber is 3.5 mm. In yet another configuration, the cap body has a front end and a rear end. In one configuration, the first chamber is adjacent to the front end of the cap body. In another configuration, the third chamber is adjacent to the rear end of the cap body. In yet another configuration, the cap body includes a flange portion and a plug portion.

[0009] In another embodiment of the present invention, a cap for a biological fluid collection device includes a cap body defining a chamber having a first diameter, the cap body having a front end and a rear end, a first vent plug disposed in the chamber, and a second vent plug including a carboxymethyl cellulose additive, the first vent plug being disposed between the second vent plug and the front end of the cap body.

[0010] In one configuration, the second vent plug allows air to pass through while preventing the blood sample from passing through. In another configuration, the second vent plug is a porous plug. In yet another configuration, the first vent plug is a porous plug. In one configuration, the second vent plug is disposed in the chamber. In another configuration, the second vent plug is a sheet that covers a portion of the rear end of the cap body. In yet another configuration, the cap body includes a flange portion and a plug portion. [Brief explanation of the drawings]

[0011] The foregoing and other features and advantages of the present disclosure, as well as the manner in which they are achieved, will become more apparent, and the disclosure itself will be better understood, by referring to the following description of embodiments of the present disclosure in conjunction with the accompanying drawings.

[0012] [Figure 1] 1 is a perspective view of a capped biological fluid collection device according to an embodiment of the present invention; [Figure 2] 1 is a perspective view of a capped biological fluid collection device according to an embodiment of the present invention; [Figure 3] FIG. 1 is a perspective view of a cap according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view of a cap according to an embodiment of the present invention. [Figure 5] 1 is a cross-sectional view of a cap with a vent plug according to an embodiment of the present invention. FIG. [Figure 6] FIG. 10 is a perspective view of a cap according to another embodiment of the present invention. [Figure 7] 7 is a graph illustrating unit bias for the cap of FIG. 6 according to an embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view of a cap according to another embodiment of the present invention. [Figure 9] 9 is a graph illustrating unit bias for the cap of FIG. 8 according to an embodiment of the present invention. [Figure 10] FIG. 10 is a cross-sectional view of a cap with a vent plug according to another embodiment of the present invention. [Figure 11] FIG. 10 is a cross-sectional view of a cap with a vent plug according to another embodiment of the present invention. [Figure 12] FIG. 10 is a cross-sectional view of a cap with a vent plug according to another embodiment of the present invention. [Figure 13] FIG. 10 is a cross-sectional view of a cap with a vent plug according to another embodiment of the present invention. [Figure 14] 1 is a perspective view of a biological fluid collection device having a collection module disposed within an outer case according to an embodiment of the present invention. [Figure 15] 15 is a partial cross-sectional perspective view of the biological fluid collection device of FIG. 14 according to an embodiment of the present invention. [Figure 16] 1 is a perspective view of a biological fluid collection device having a collection module disposed within an outer case according to an embodiment of the present invention. [Figure 17]17 is a partial cross-sectional perspective view of the biological fluid collection device of FIG. 16 according to an embodiment of the present invention. FIG. [Figure 18A] 1 is a partial cross-sectional perspective view of a biological fluid collection device being inserted into a tube holder according to an embodiment of the present invention. FIG. [Figure 18B] 1 is a partial cross-sectional perspective view of a biological fluid collection device according to an embodiment of the present invention, showing a biological fluid sample flowing through a tube holder and into a collection module. FIG. [Figure 18C] 1 is a partial cross-sectional perspective view of a biological fluid collection device being removed from a tube holder according to an embodiment of the present invention. FIG. [Figure 18D] 1 is a partial cross-sectional perspective view of a collection module of a biological fluid collection device removed from an outer case, according to an embodiment of the present invention. FIG. [Figure 18E] 1 is a partial cross-sectional perspective view showing a cap being removed from a collection module of a biological fluid collection device according to an embodiment of the present invention. FIG. [Figure 18F] 1 is a partial cross-sectional perspective view illustrating actuation of an actuation member of a collection module of a biological fluid collection device to expel biological fluid from the collection module, according to an embodiment of the present invention. FIG. [Figure 19] 1 is a partial perspective view of the lower end of a biological fluid collection device having a biological fluid collection module disposed within an outer collection case according to an embodiment of the present invention. FIG. [Figure 20] 1 is a partial cross-sectional perspective view of the lower end of a biological fluid collection device according to an embodiment of the present invention. FIG. [Figure 21] 1 is a perspective view of a biological fluid collection device according to an embodiment of the present invention.

[0013] Corresponding reference characters indicate corresponding parts throughout the several views. The examples described herein illustrate examples of embodiments of the present disclosure, and the examples are not to be construed as limiting the scope of the disclosure in any way. DETAILED DESCRIPTION OF THE INVENTION

[0014] The following description is provided to enable those skilled in the art to make and use the embodiments described herein that are contemplated for practicing the invention. However, various modifications, equivalents, variations, and alternatives will be readily apparent to those skilled in the art. All such modifications, variations, equivalents, and alternatives are intended to be within the spirit and scope of the invention.

[0015] For purposes of the following description, the terms "upper," "lower," "right," "left," "vertical," "horizontal," "top," "bottom," "sideways," "longitudinal," and derivatives thereof, refer to the present invention as oriented in the drawings. However, it should be understood that the present invention can assume various alternative modifications unless expressly specified otherwise. It should also be understood that the specific devices illustrated in the accompanying drawings and described in the following specification are merely exemplary embodiments of the present invention. Hence, specific dimensions and other physical characteristics related to the embodiments disclosed herein are not to be considered limiting.

[0016] The present disclosure provides a cap with a vent plug for a biological fluid collection device. The vent plug allows the passage of air while preventing the passage of a blood sample. In one embodiment, the vent plug is a porous plug. In one embodiment, the cap includes a vent plug that includes a carboxymethyl cellulose additive.

[0017] Carboxymethylcellulose is a "self-sealing" additive that swells upon contact with liquid. When this additive is placed within a porous material, especially a hydrophobic material, it allows air to escape, then swells and closes when liquid reaches the carboxymethylcellulose. This prevents liquid from leaking out of the collection chamber of a biological fluid collection device. Carboxymethylcellulose is effective in preventing analyte bias (typically Ca) in small blood sample volumes (<5 mL). 2+ , Na + , K. + ) can occur.

[0018] When membranes with carboxymethylcellulose additives are exposed to blood or the fluid of interest at high surface contact area-to-volume ratios, this can dramatically affect analyte bias results in blood. Ion exchange occurring between the carboxymethylcellulose additive and ions in plasma can lead to erroneous results.

[0019] In one embodiment, the cap of the present disclosure limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose by reducing the contact area, e.g., reducing the radius, between the blood and the carboxymethylcellulose additive.

[0020] In one embodiment, the cap of the present disclosure increases the path length between the blood and the carboxymethyl cellulose additive, for example, by increasing the path length, it limits analyte bias due to the interaction of plasma ions with the carboxymethyl cellulose.

[0021] In one embodiment, the cap of the present disclosure limits analyte bias due to plasma ion interactions with carboxymethylcellulose by introducing a porous material in front of the carboxymethylcellulose additive plug to reduce the diffusivity.

[0022] The disclosed cap reduces the rate at which bias ions can move away from the carboxymethyl cellulose source and into the blood, i.e., the measurement sample. The disclosed cap is of particular interest for small blood volumes (<5 mL) where carboxymethyl cellulose additives can dramatically affect ion concentrations.

[0023] The present disclosure provides a cap with a vent plug for a biological fluid collection device. The cap of the present disclosure fits onto a biological fluid collection device 1 as shown in Figures 14-21.

[0024] 14 and 15, in one embodiment, a biological fluid collection device 1 includes a collection module 10 disposed within an outer case 34. The collection module 10 is adapted to receive a biological fluid sample, such as a blood sample, and includes a case 12, a closure 14, a mixing chamber 16, a holding chamber 18, a cap 20, and an actuation member 22.

[0025] In one embodiment, the case 12 includes a first end 24, a second end 26, and a flow passage 28 extending between and providing fluid communication between the first end 24 and the second end 26 of the case 12. The flow path 28 has a sample introduction opening 30 at the first end 24 of the case 12 and a sample discharge opening 32 at the second end 26 of the case 12. The mixing chamber 16 and the holding chamber 18 are in fluid communication with the flow path 28. The mixing chamber 16 and the holding chamber 18 are positioned such that a biological fluid sample, such as a blood sample, introduced through the sample introduction opening 30 of the flow path 28 first passes through the mixing chamber 16, then enters the holding chamber 18, and reaches the sample discharge opening 32 of the flow path 28. This allows the blood sample to be mixed with an additive, such as an anticoagulant additive, in the mixing chamber 16, and the stabilized sample to be received and stored in the holding chamber 18.

[0026] The mixing chamber 16 allows for passive mixing of the blood sample with other additives, such as anticoagulants or blood stabilizers, as the blood sample flows through the flow path 28. The interior of the mixing chamber 16 may have any suitable structure or configuration, so long as the blood sample can mix with the anticoagulant or other additives as the blood sample passes through the flow path 28. The mixing chamber 16 may include a dry anticoagulant, such as heparin or EDTA, on or within the mixing chamber 16. The mixing chamber 16 may include, for example, an open-cell foam with the dry anticoagulant dispersed within the bubbles to promote effective fluid mixing and anticoagulant uptake.

[0027] The open-cell foam may be treated with an anticoagulant to provide a fine distribution of dry anticoagulant powder throughout the cells of the open-cell foam. As the blood sample enters the mixing chamber 16, it passes through the open-cell foam and is exposed to the anticoagulant powder available throughout the interior cell structure of the open-cell foam.

[0028] The open-cell foam may be a soft, deformable, open-cell foam that is inert to blood, such as a melamine foam, such as Basotect® foam available from BASF. It may also be comprised of a formaldehyde-melamine-sodium bisulfite copolymer. The open-cell foam may also be a flexible, hydrophilic, open-cell foam that is substantially resistant to heat and organic solvents. In one embodiment, the foam may comprise a sponge material.

[0029] Anticoagulants or other additives may be introduced into open-cell foams by immersing the foam in a solution of the additive and water, followed by evaporation of the water to finely distribute the dry additive powder throughout the internal structure of the foam.

[0030] After passing through the mixing chamber 16, the blood sample may be directed to a holding chamber 18. The holding chamber 18 may have any suitable shape and size capable of storing a sufficient volume of blood required for the desired test, e.g., 500 μl or less. In one embodiment, the holding chamber 18 is defined by a portion of the case 12 in combination with an elastic sleeve 40 secured around the exterior of the case 12. The elastic sleeve 40 may be made of any flexible, deformable material capable of forming a fluid-tight seal with the case 12, such as, but not limited to, natural or synthetic rubber or other suitable elastomeric material. The case 12 includes a recess 42 that extends from the exterior of the case 12 to the flow channel 28, effectively forming an opening in the case 12 that is in fluid communication with the flow channel 28. The elastic sleeve 40 covers the recess 42, thereby defining the holding chamber 18 with an internal fill volume of 500 μl or less.

[0031] A cap 20 disposed at the second end 26 of the case 12 covers the sample outlet opening 32 of the flow path 28. Referring to FIGS. 1-5, the cap 20 of the present disclosure includes a vent plug 44 that allows air to pass through while preventing the blood sample from passing through. In one embodiment, the vent plug 44 is a porous plug. In one embodiment, the cap 20 includes a vent plug 44 that includes a carboxymethyl cellulose additive.

[0032] Referring to FIG. 15 , in one embodiment, the cap 20 includes a vent plug 44, such as a porous plug, extending from the inner surface of the cap 20 to the outer surface of the cap 20. The structure of the vent plug 44 allows air to pass through the cap 20 while preventing the blood sample from passing through the cap 20. The structure of the vent plug 44 may include a hydrophobic filter. The vent plug 44 has a selected air resistance, which can be used to finely control the fill rate of the flow channel 28. By varying the porosity of the plug, the rate of airflow out of the cap 20 and, therefore, the rate of blood sample flow into the collection module 10 can be controlled. Flowing the blood sample too quickly into the collection module 10 can cause hemolysis. Flowing the blood sample too slowly into the collection module 10 can result in excessively long sample collection times.

[0033] Closure 14 engages first end 24 of case 12 to seal flow path 28. Closure 14 allows for the introduction of a blood sample into flow path 28 of case 12 and may include a pierceable, self-sealing stopper 36 having an outer shield 38, such as a Hemogaid® cap available from Becton, Dickinson & Company. Closure 14 is also secured to outer case 34, which may be a vacuum-containing blood collection tube, such as a Vacutainer® blood collection tube available from Becton, Dickinson & Company.

[0034] Additionally, the cap 20 disposed on the second end 26 of the case 12 may include a flange 46 to assist a user in removing the cap 20 from the case 12. As shown in Figure 15, the flange 46 may have an outer diameter that is smaller than the inner diameter of the outer case 34 in which the collection module 10 may be disposed. Alternatively, as shown in Figures 19 and 20, the flange 46 may have an outer diameter that is substantially equal to the inner diameter of the outer case 34. In this configuration, flange 46 may include a recess or slot 48 extending from the top to the bottom to allow the vacuum within outer casing 34 to pass around flange 46. Additionally, as shown in Figures 19 and 20, flange 46 may be made of an optically transparent material and may have a convex outer diameter surface to enlarge the area of ​​vent plug 44 on cap 20, allowing medical personnel to know when the blood sample has completely filled flow path 28 and reached cap 20. Flange 46 may also engage a recess in the interior wall of outer casing 34 to hold cap 20 in place.

[0035] In use, a needle cannula 50 (FIGS. 18A and 18C) is inserted through the sample introduction opening 30, for example, through the pierceable self-sealing stopper 36 of the closure 14, and into the flow path 28 of the case 12. As shown in FIG. 18A, the combined collection module 10 and outer case 34 may be inserted into a conventional tube holder 52 having a cannula through which biological fluid is passed.

[0036] The biological fluid sample is drawn from a conventional tube holder 52 into the flow path 28 of the case 12 by the drawing of a vacuum contained within the outer case 34 (FIG. 18B). The blood sample first enters the mixing chamber 16 and then the holding chamber 18, filling the entire flow path 28 and expelling any air present in the flow path 28 into the outer case 34. As described above, as the biological fluid sample passes through the mixing chamber 16, it is exposed to and mixed with anticoagulants or other additives. The cap 20 stops the collection of the blood sample when the flow path 28, mixing chamber 16, and holding chamber 18 of the collection module 10 are completely filled. The vent plug 44 on the cap 20 prevents blood from entering the outer case 34.

[0037] Once sample collection is complete, the outer case 34 containing the collection module 10 is separated from the tube holder 52 (FIG. 18C), and then the outer case 34 is separated from the collection module 10 by removing the closure 14, which is still attached to the collection module 10, from the outer case 34 (FIG. 18D). Removal of the closure 14 may be accomplished by the user grasping both the outer shield 38 and the outer case 34 of the closure 14 and pulling or twisting them in opposite directions.

[0038] Once the collection module 10 is separated from the outer case 34, the cap 20 can then be removed from the collection module 10 (FIG. 18E), exposing the second end 26 of the case 12. Removal may be accomplished by a user grasping the flange 46 and pulling the cap 20 from the case 12. The blood sample is retained within the flow channel 28 of the case 12 by capillary action after the cap 20 is removed. Alternatively, the cap 20 may be removed when the collection module 10 is removed from the outer case 34. In this configuration, the cap 20 is retained within the outer case 34 by the interaction of the flange 46 with a corresponding recess in the outer case wall. In one embodiment, the cap 20 may be connected to the outer case 34 such that the outer case 34 and cap 20 are removed in a single step.

[0039] The blood sample is then ejected from collection module 10 by actuation of actuation member 22, for example, by applying inward pressure in the direction of the arrow to a portion of elastomeric sleeve 40 covering holding chamber 18, forcing the blood sample out of holding chamber 18 through sample ejection opening 32 (FIG. 18F). In this manner, the blood sample can be transferred to a device intended to analyze the blood sample, for example, a point-of-care testing device such as a cartridge tester, or through the opening while minimizing exposure of medical personnel to the blood sample.

[0040] Although a portion of elastomeric sleeve 40 has been shown and described as partially defining holding chamber 18 and functioning as actuation member 22 for ejecting the blood sample from collection module 10, other alternative configurations are envisioned for achieving the same result. For example, holding chamber 18 may be defined entirely by case 12, and a separate actuator engaging holding chamber 18 may be actuated to eject the blood sample. Actuation devices may include, but are not limited to, plungers, push buttons, slides, etc.

[0041] In another embodiment, shown in Figures 16 and 17, closure 14 may have a luer lock connection 54 that passes through stopper 36. This configuration is useful for collecting blood samples from an artery where a vacuum is not required to draw the blood sample into collection module 100, as is necessary for venous blood collection (Figures 16 and 17). Collection module 100 is used similarly to collection module 10, except that luer lock connection 54 is used to connect collection module 100 to a wingset or other collection means having a mating luer lock connection that introduces the blood sample into flow path 28.

[0042] Additionally, the collection modules 10, 100 may be used without the outer case 34. With the collection module 10, a syringe or other power source may be used to draw a sample into the collection module 10. Additionally, although the collection modules 10, 100 have been primarily described herein as being used to collect blood samples and mix them with anticoagulants or other additives, the collection modules 10, 100 may also be used to collect any liquid sample, such as other bodily fluids, or to mix and dispense samples already collected by other means.

[0043] In a further configuration, the collection module 10 may include labels 56a, 56b attached to both the closure 14 and the outer case 34 that must be severed to remove the collection module 10 from the outer case 34. As shown in FIGS. 14-17, the label 56a may be a strip that extends only along a portion of the circumference of the closure 14 and the outer case 34. When the closure 14 is twisted relative to the outer case 34, the strip breaks between the outer case 34 and the closure 14. Perforations 58 may be provided in the label 56a between the outer case 34 and the closure 14 to assist in breaking the strip when the closure 14 is twisted. Alternatively, as shown in FIG. 21, the label 56b may surround the entire circumference of both the closure 14 and the outer case 34. Between the outer case 34 and the closure 14, the label 56b may include perforations 58 to form a band 60 around the periphery of the closure 14 such that the band 60 separates from the portion of the label 56b that surrounds the outer case 34. Removing the band 60 from the closure 14 allows the closure 14 to be removed from the outer case 34. A pull tab 62 may be provided on the band 60 to assist in separating the band 60 from the portion of the label 56b that surrounds the outer case 34.

[0044] 1-5, the cap 20 of the present disclosure includes a vent plug 44 that allows air to pass through while preventing a blood sample from passing through. In one embodiment, the vent plug 44 is a porous plug. In one embodiment, the cap 20 includes a vent plug 44 that includes a carboxymethyl cellulose additive.

[0045] The cap of the present disclosure is compatible with any collection chamber of a biological fluid collection device. The cap of the present disclosure may be used to remove air before sealing liquid within the chamber. For example, the cap of the present disclosure is compatible with the biological fluid collection devices shown in Figures 14 through 18F. The cap of the present disclosure is also compatible with the biological fluid collection devices shown in Figures 1 and 2. Furthermore, the cap of the present disclosure is also compatible with other biological fluid collection devices having a collection chamber.

[0046] Carboxymethylcellulose is a "self-sealing" additive that swells upon contact with liquid. When this additive is placed within a porous material, especially a hydrophobic material, it allows air to escape, then swells and closes when liquid reaches the carboxymethylcellulose. This prevents liquid from leaking out of the collection chamber of a biological fluid collection device. Carboxymethylcellulose is effective in preventing analyte bias (typically Ca) in small blood sample volumes (<5 mL). 2+ , Na + , K. + ) can be generated.

[0047] When membranes with carboxymethylcellulose additives are exposed to blood or the fluid of interest at high surface contact area-to-volume ratios, this can dramatically affect analyte bias results in blood. Ion exchange occurring between the carboxymethylcellulose additive and ions in plasma can lead to erroneous results.

[0048] In one embodiment, the cap 20 of the present disclosure limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose by reducing the contact area, e.g., reducing the radius, between the blood and the carboxymethylcellulose additive.

[0049] In one embodiment, the cap 20 of the present disclosure increases the path length between the blood and the carboxymethylcellulose additive, for example, by increasing the path length, it limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose.

[0050] In one embodiment, the cap 20 of the present disclosure limits analyte bias due to plasma ion interactions with carboxymethylcellulose by introducing a porous material in front of the carboxymethylcellulose additive plug to reduce the diffusivity.

[0051] The cap 20 of the present disclosure reduces the rate at which bias ions can move away from the carboxymethyl cellulose source and into the blood, i.e., the measurement sample. The cap 20 of the present disclosure is of particular interest for small blood volumes (<5 mL) where the carboxymethyl cellulose additive can dramatically affect ion concentrations.

[0052] 1-5, the cap 20 includes a cap body 70 and a vent plug 44. In one embodiment, the cap body 70 defines a first chamber 72 having a first diameter D1, a second chamber 74 having a second diameter D2, and a third chamber 76 having a third diameter D3. In one embodiment, the second chamber 74 is between the first chamber 72 and the third chamber 76. In one embodiment, the second diameter D2 is smaller than the first diameter D1. In one embodiment, the second diameter D2 is smaller than the third diameter D3. In one embodiment, the first diameter D1 is smaller than the third diameter D3. In one embodiment, the first diameter D1 is 1.016 mm, the second diameter D2 is 0.4 mm, and the third diameter D3 is 1.5 mm. In one embodiment, the length of the second chamber 74 is 1.6 mm, and the length of the third chamber 76 is 3.5 mm.

[0053] By reducing the diameter of the second chamber 74, the cap 20 of the present disclosure reduces the contact area between the blood and the carboxymethylcellulose additive, e.g., by reducing the radius, thereby limiting analyte bias due to the interaction of plasma ions with the carboxymethylcellulose.

[0054] In one embodiment, a vent plug 44 is disposed in the third chamber 76. In one embodiment, the vent plug 44 includes a carboxymethyl cellulose additive. The vent plug 44 allows air to pass through the cap 20 while preventing the blood sample from passing through. In one embodiment, the vent plug 44 is a porous plug. The structure of the vent plug 44 allows air to pass through the cap 20 while preventing the blood sample from passing through the cap 20. The structure of the vent plug 44 may include a hydrophobic filter. The vent plug 44 has a selected air resistance, which can be used to precisely control the fill rate of the flow passage 28. By varying the porosity of the plug, the rate of air flow out of the cap 20 and, therefore, the rate of blood sample flow into the collection module 10 can be controlled.

[0055] 4 and 5, in one embodiment, the cap body 70 has a front end 80 and a rear end 82. In one embodiment, the first chamber 72 is adjacent the front end 80 of the cap body 70, and the third chamber 76 is adjacent the rear end 82 of the cap body 70.

[0056] In one embodiment, the cap body 70 includes a flange portion 84 and a plug portion 86. The flange portion 84 can be used to assist a user in removing the cap 20 from the case 12. As shown in FIGS. 1 and 2 , the flange portion 84 may have an outer diameter that is larger than the inner diameter of the outer case 34 in which the collection module 10 can be placed. Alternatively, the flange portion 84 may have an outer diameter that is substantially equal to or less than the inner diameter of the outer case 34. Additionally, as shown in FIGS. 19 and 20 , the flanges 46, 84 may be made of an optically transparent material and have a convex outer diameter surface to enlarge the area of ​​the vent plug 44 on the cap 20, allowing medical personnel to know when the blood sample has completely filled the flow path 28 and reached the cap 20. The flanges 46, 84 may also engage recesses in the inner wall of the outer case 34 to hold the cap 20 in place.

[0057] In another embodiment, referring to Figures 11 and 12, a cap 120 of the present disclosure has a first vent plug 122 and a second vent plug 124 that includes a carboxymethyl cellulose additive.

[0058] Carboxymethylcellulose is a "self-sealing" additive that swells upon contact with liquid. When this additive is placed within a porous material, especially a hydrophobic material, it allows air to escape, then swells and closes when liquid reaches the carboxymethylcellulose. This prevents liquid from leaking out of the collection chamber of a biological fluid collection device. Carboxymethylcellulose is effective in preventing analyte bias (typically Ca) in small blood sample volumes (<5 mL). 2+ , Na + , K. +) can be generated.

[0059] When membranes with carboxymethylcellulose additives are exposed to blood or the fluid of interest at high surface contact area-to-volume ratios, this can dramatically affect analyte bias results in blood. Ion exchange occurring between the carboxymethylcellulose additive and ions in plasma can lead to erroneous results.

[0060] In one embodiment, the cap 120 of the present disclosure limits analyte bias due to plasma ion interactions with carboxymethylcellulose by introducing a porous material in front of the carboxymethylcellulose additive plug to reduce the diffusivity.

[0061] The cap 120 of the present disclosure reduces the rate at which bias ions can move away from the carboxymethyl cellulose source and into the blood, i.e., the measurement sample. The cap 120 of the present disclosure is of particular interest for small blood volumes (<5 mL) where the carboxymethyl cellulose additive can dramatically affect ion concentrations.

[0062] 11 and 12 , cap 120 includes a cap body 170, a first vent plug 122, and a second vent plug 124. In one embodiment, cap body 170 defines a chamber 172 having a first diameter D1. Cap body 170 has a front end 180 and a rear end 182. In one embodiment, chamber 172 extends from front end 180 to rear end 182.

[0063] In one embodiment, cap body 170 includes a flange portion 184 and a plug portion 186. Flange portion 184 may be used to assist a user in removing cap 20 from case 12. As shown in FIGS. 11 and 12 , flange portion 184 may have an outer diameter that is substantially equal to or less than the inner diameter of outer case 34. Additionally, as shown in FIGS. 19 and 20 , flanges 46, 184 may be made of an optically transparent material and may have a convex outer diameter surface to enlarge the vent plug area of ​​cap 120, allowing medical personnel to know when the blood sample has completely filled flow path 28 and reached cap 120. Additionally, flanges 46, 184 may engage recesses in the inner walls of outer case 34 to hold cap 120 in place.

[0064] In one embodiment, first vent plug 122 is disposed in chamber 172. In one embodiment, second vent plug 124 includes a carboxymethyl cellulose additive. In one embodiment, first vent plug 122 is disposed between second vent plug 124 and front end 180 of cap body 170.

[0065] The second vent plug 124 allows air to pass through but prevents the blood sample from passing through. In one embodiment, the first vent plug 122 is a porous plug. In one embodiment, the second vent plug 124 is a porous plug.

[0066] The structure of the second vent plug 124 allows air to pass through the cap 120 while preventing the blood sample from passing through the cap 120. The structure of the second vent plug 124 may include a hydrophobic filter. The second vent plug 124 has a selected air resistance that can be used to finely control the fill rate of the flow passage 28. By varying the porosity of the plug, the rate of air flow out of the cap 120, and therefore the rate of blood sample flow into the collection module 10, can be controlled.

[0067] Referring to FIG. 11, in one embodiment, the second vent plug 124 is a sheet 190 that covers a portion of the rear end 182 of the cap body 170 .

[0068] Referring to FIG. 12, in one embodiment, the second vent plug 124 is positioned in the chamber 172 of the cap body 170, and the first vent plug 122 is positioned between the second vent plug 124 and the front end 180 of the cap body 170.

[0069] By including a first vent plug 122 upstream of a second vent plug 124 containing a carboxymethyl cellulose additive, the cap 120 of the present disclosure limits analyte bias due to plasma ion interaction with the carboxymethyl cellulose by introducing a porous material in front of the carboxymethyl cellulose additive plug to reduce the diffusivity.

[0070] Diffusion in porous materials can be reduced by decreasing the porosity or contractility of the material and increasing tortuosity. In one embodiment, a cap having a first vent plug 122 and a second vent plug 124 with a carboxymethyl cellulose additive function independently, as shown in Figures 11 and 12.

[0071] In another embodiment, a cap having a first vent plug 122 and a second vent plug 124 containing a carboxymethyl cellulose additive, as shown in Figures 11 and 12, can be combined with a cap body 70 defining a first chamber 72 having a first diameter D1, a second chamber 74 having a second diameter D2, and a third chamber 76 having a third diameter D3, as shown in Figure 4. Either embodiment advantageously results in a reduced rate of analyte bias in samples sealed with the carboxymethyl cellulose porous plug.

[0072] Referring to FIG. 13, in another embodiment, a cap 220 of the present disclosure has a first vent plug 222 that includes a carboxymethyl cellulose additive and a second vent plug 224 that includes a carboxymethyl cellulose additive.

[0073] Carboxymethylcellulose is a "self-sealing" additive that swells upon contact with liquid. When this additive is placed within a porous material, especially a hydrophobic material, it allows air to escape, then swells and closes when liquid reaches the carboxymethylcellulose. This prevents liquid from leaking out of the collection chamber of a biological fluid collection device. Carboxymethylcellulose is effective in preventing analyte bias (typically Ca) in small blood sample volumes (<5 mL). 2+ , Na + , K. + ) can be generated.

[0074] When membranes with carboxymethylcellulose additives are exposed to blood or the fluid of interest at high surface contact area-to-volume ratios, this can dramatically affect analyte bias results in blood. Ion exchange occurring between the carboxymethylcellulose additive and ions in plasma can lead to erroneous results.

[0075] In one embodiment, the cap 220 of the present disclosure limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose by reducing the contact area, e.g., reducing the radius, between the blood and the carboxymethylcellulose additive.

[0076] In one embodiment, the cap 220 of the present disclosure increases the path length between the blood and the carboxymethylcellulose additive, for example, by increasing the path length, it limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose.

[0077] The cap 220 of the present disclosure reduces the rate at which bias ions can move away from the carboxymethyl cellulose source and into the blood, i.e., the measurement sample. The cap 220 of the present disclosure is of particular interest for small blood volumes (<5 mL) where the carboxymethyl cellulose additive can dramatically affect ion concentrations.

[0078] 13 , cap 220 includes a cap body 270, a first vent plug 222, and a second vent plug 224. In one embodiment, cap body 270 defines a first chamber 272 having a first diameter D1, a second chamber 274 having a second diameter D2, and a pair of third chambers 276 having a third diameter D3. In one embodiment, second chamber 274 is located between first chamber 272 and third chamber 276. In one embodiment, second diameter D2 is smaller than first diameter D1. In one embodiment, second diameter D2 is smaller than third diameter D3.

[0079] By reducing the diameter of the second chamber 274, the cap 220 of the present disclosure reduces the contact area between the blood and the carboxymethylcellulose additive, e.g., by reducing the radius, thereby limiting analyte bias due to the interaction of plasma ions with the carboxymethylcellulose.

[0080] 13 , in one embodiment, second chamber 274 has first channel 277, second channel 278, and third channel 279. In one embodiment, one side of third chamber 276 communicates with first chamber 272 via first channel 277 and second channel 278, and the other side of third chamber 276 communicates with first chamber 272 via first channel 277 and third channel 279.

[0081] By having a first channel 277, a second channel 278, and a third channel 279, and by having a second chamber 274 that extends the path length between the first chamber 272 and the third chamber 276, the cap 220 of the present disclosure increases the path length between the blood and the carboxymethylcellulose additive, e.g., by increasing the path length, it limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose.

[0082] In one embodiment, a first vent plug 222 is disposed on one side of the third chamber 276. In one embodiment, the first vent plug 222 includes a carboxymethyl cellulose additive. In one embodiment, a second vent plug 224 is disposed on the other side of the third chamber 276. In one embodiment, the second vent plug 224 includes a carboxymethyl cellulose additive.

[0083] First vent plug 222 and second vent plug 224 allow the passage of air but prevent the passage of a blood sample. In one embodiment, first vent plug 222 is a porous plug. In one embodiment, second vent plug 224 is a porous plug.

[0084] The structure of the first vent plug 222 and the second vent plug 224 allows air to pass through the cap 220 while preventing the blood sample from passing through the cap 220. The structure of the first vent plug 222 and the second vent plug 224 may include a hydrophobic filter. Each of the first vent plug 222 and the second vent plug 224 has a selected air resistance that can be used to finely control the fill rate of the flow passage 28. By varying the porosity of the plugs, the rate of air flow out of the cap 220, and therefore the rate of blood sample flow into the collection module 10, can be controlled.

[0085] In one embodiment, the present disclosure provides a cap that limits analyte bias due to the interaction of plasma ions with the carboxymethylcellulose by reducing the contact area, e.g., reducing the radius, between the blood and the carboxymethylcellulose additive.

[0086] In one embodiment, the present disclosure provides a cap that increases the path length between the blood and the carboxymethyl cellulose additive, e.g., by increasing the path length, limits analyte bias due to the interaction of plasma ions with the carboxymethyl cellulose.

[0087] In one embodiment, the present disclosure provides a cap that introduces a porous material in front of the carboxymethyl cellulose additive plug to reduce diffusivity and thereby limit analyte bias due to plasma ion interactions with the carboxymethyl cellulose.

[0088] The disclosed cap reduces the rate at which bias ions can move away from the carboxymethyl cellulose source and into the blood, i.e., the measurement sample. The disclosed cap is of particular interest for small blood volumes (<5 mL) where carboxymethyl cellulose additives can dramatically affect ion concentrations.

[0089] While this disclosure has been described as having exemplary designs, the disclosure can be further modified within the spirit and scope of the disclosure. Accordingly, this application is intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the disclosure as come within known practice or custom in the art to which this disclosure pertains and fall within the limits of the appended claims.

[0090] Other embodiment 1 The present invention provides a cap for a biological fluid collection device, the cap including a cap body defining a chamber and having a vent plug disposed therein, the vent plug being a cap including a carboxymethyl cellulose additive.

[0091] In the present invention, the chamber of the cap body is a first chamber having a first diameter, and the cap body further defines a second chamber having a second diameter and a third chamber having a third diameter, the second chamber is disposed between the first chamber and the third chamber, and the vent plug is disposed in the third chamber.

[0092] In the present invention, the second diameter may be smaller than the first diameter. Also, in the present invention, the second diameter may be smaller than the third diameter.

[0093] In the present invention, the first diameter may be smaller than the third diameter.

[0094] In the present invention, the first diameter may be 1.016 mm, the second diameter may be 0.4 mm, and the third diameter may be 1.5 mm.

[0095] In the present invention, the length of the second chamber may be 1.6 mm, and the length of the third chamber may be 3.5 mm.

[0096] In the present invention, the first chamber may be adjacent to a front end of the cap body, and the third chamber may be adjacent to a rear end of the cap body.

[0097] In the present invention, the vent plug may allow air to pass through but prevent the blood sample from passing through.

[0098] In the present invention, the vent plug may be a porous plug.

[0099] The present invention provides a cap for a biological fluid collection device, the cap including a cap body defining a chamber having a first diameter and having a front end and a rear end, a first vent plug disposed in the chamber, and a second vent plug including a carboxymethyl cellulose additive, the first vent plug being a cap disposed between the second vent plug and the front end of the cap body.

[0100] In the present invention, the second vent plug may allow air to pass through but prevent the blood sample from passing through.

[0101] In the present invention, the second vent plug may be a porous plug.

[0102] In the present invention, the first vent plug may be a porous plug.

[0103] In the present invention, the second vent plug may be disposed in the chamber.

[0104] In the present invention, the second vent plug may be a sheet that covers a portion of the rear end portion of the cap body.

[0105] [Other embodiment 2] The present invention provides a cap for a biological fluid collection device, comprising a cap body defining a chamber having an opening at a front end and an opening at a rear end, and a vent plug positioned outside the chamber in the cap body and covering the opening at the rear end of the chamber, wherein the vent plug may be a cap containing a carboxymethyl cellulose additive.

[0106] In the present invention, the chamber of the cap body is a first chamber having a first diameter, and the cap body further defines a second chamber having a second diameter and a third chamber having a third diameter, the second chamber is disposed between the first chamber and the third chamber, and the vent plug is disposed in the third chamber.

[0107] In the present invention, the second diameter may be smaller than the first diameter, and the second diameter may be smaller than the third diameter.

[0108] In the present invention, the first diameter may be smaller than the third diameter.

[0109] In the present invention, the first diameter may be 1.016 mm, the second diameter may be 0.4 mm, and the third diameter may be 1.5 mm.

[0110] In the present invention, the second chamber may have a length of 1.6 mm, and the third chamber may have a length of 3.5 mm.

[0111] In the present invention, the first chamber may be adjacent to the front end of the cap body, and the third chamber may be adjacent to the rear end of the cap body.

[0112] In the present invention, the vent plug may allow air to pass through but prevent the blood sample from passing through.

[0113] In the present invention, the vent plug may be a porous plug.

[0114] The present invention may further include a second vent plug disposed in the chamber.

[0115] Other embodiment 3 The present invention provides a cap for a biological fluid collection device, the cap including a cap body defining a front end, a rear end opposite the front end, a first chamber adjacent the front end, a second chamber in fluid communication with the first chamber, and a third chamber in fluid communication with the first chamber; a first vent plug disposed in the second chamber of the cap body; and a second vent plug disposed in the third chamber of the cap body, each of the first vent plug and the second vent plug being a cap containing a carboxymethyl cellulose additive.

[0116] In the present invention, the cap body may further define a fourth chamber between the first chamber and the second chamber.

[0117] In the present invention, the fourth chamber may be between the first chamber and the third chamber.

[0118] In the present invention, the first chamber has a first diameter, the second chamber has a second diameter, the third chamber has a third diameter, and the fourth chamber has a fourth diameter, and the fourth diameter may be smaller than the first diameter.

[0119] In the present invention, the fourth diameter may be smaller than the second diameter.

[0120] In the present invention, the second diameter and the third diameter may be equal.

[0121] In the present invention, the cap body may further define a first channel extending from the first chamber, a second channel extending from the first channel to the second chamber, and a third channel extending from the first channel to the third chamber.

[0122] In the present invention, the first channel may be substantially orthogonal to the second and third channels.

[0123] In the present invention, the second channel may be substantially parallel to the third channel.

Claims

1. A blood collection tube; a collection module disposed within the blood collection tube, the collection module having a first end, a second end opposite the first end and positioned within the blood collection tube, and a flow path extending therebetween; a cap body mounted within the blood collection tube at the second end of the collection module, the cap body defining a passageway therethrough; and a first vent plug disposed within the passageway, the first vent plug including a carboxymethyl cellulose additive, the first vent plug configured to allow air to flow from the flow passage, through the passageway in the cap body, and into the blood collection tube; 1. A biological fluid collection device comprising:

2. 10. The biological fluid collection device of claim 1, further comprising a stopper sealing an opening in the blood collection tube.

3. 3. The biological fluid collection device of claim 2, wherein the first end of the collection module is attached to the stopper.

4. The cap body is a plug portion at a front end of the cap body, the plug portion configured to be positioned within the flow path of the collection module; a flange portion at a rear end of the cap body, the flange portion having an outer diameter greater than an outer diameter of the plug portion and configured to abut the second end of the collection module; The biological fluid collection device of claim 1 , defining:

5. The cap body is a first chamber having a first diameter; a second chamber having a second diameter; a third chamber having a third diameter; Define the the second chamber is disposed between the first chamber and the third chamber, and the pathway extends through the first, second, and third chambers; 10. The biological fluid collection device of claim 1.

6. 6. The biological fluid collection device of claim 5, wherein the first chamber includes a first opening at a front end of the cap body, and the third chamber includes an opening at a rear end of the cap body.

7. 6. The biological fluid collection device of claim 5, wherein the second diameter is smaller than the first diameter and the second diameter is smaller than the third diameter.

8. 6. The biological fluid collection device of claim 5, wherein the first diameter is smaller than the third diameter.

9. 6. The biological fluid collection device of claim 5, wherein the first vent plug is disposed within the third chamber.

10. 10. The biological fluid collection device of claim 1, further comprising a second vent plug disposed within said passageway of said cap body, said second vent plug being a porous plug.

11. 11. The biological fluid collection device of claim 10, wherein the second vent plug is disposed between the first vent plug and the flow path of the collection module.

12. 11. The biological fluid collection device of claim 10, wherein the second vent plug has a porosity different from the porosity of the first vent plug.

13. 10. The biological fluid collection device of claim 1, wherein the collection module includes an actuation member configured to apply an inward pressure within the flow path.

14. 14. The biological fluid collection device of claim 13, wherein the actuation member comprises a resilient sleeve covering at least a portion of the flow path.

15. 10. The biological fluid collection device of claim 1, wherein the cap body is constructed from an optically transparent material.

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