Bone marrow sample filtering device, sample tube and filtering method

Abstract

The invention discloses a bone marrow sample filtering device, a sample tube and a filtering method, and relates to the technical field of medical instruments.The bone marrow sample filtering device comprises an annular filtering frame and a filtering layer, and the outer side wall of the annular filtering frame can be in sealed contact with the inner side wall of the sample tube; the annular filter frame can axially move in the sample tube along the sample tube; the filter layer is fixedly arranged on the inner side of the annular filter frame, can shield the inner side space of the annular filter frame, and is matched with the annular filter frame to divide the interior of the sample pipe into an upper layer and a lower layer, so that the bone marrow sample solution is filtered. According to the bone marrow sample filtering device, the sample tube and the filtering method provided by the invention, the bone marrow sample filtering time is short, the efficiency is high, the operation is simple and convenient, and sample pollution is not easily caused.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a bone marrow sample filtering device, sample tube, and filtering method. Background Technology

[0002] In flow cytometry analysis of bone marrow samples, whole blood and whole bone marrow hemolysis labeling methods are generally used, and there are certain requirements for the total white blood cell count added to the sample tube. Therefore, the required sample volume needs to be determined based on the white blood cell count of the sample to be labeled. However, currently available hematology counters and newly launched large-scale automated flow cytometry sample pretreatment equipment cannot directly insert bone marrow sample tubes for testing or pretreatment. This is because bone marrow fluid contains tiny bone fragments, fat droplets, and a large number of bone marrow particles (composed of hematopoietic cells, stromal cells, fibrous tissue, etc.), which vary greatly in diameter (ranging from tens to hundreds of micrometers), easily clogging the injection needle and causing equipment malfunction. Therefore, before using a hematology counter to test bone marrow samples or before using automated flow cytometry sample pretreatment equipment, the bone marrow sample in the clinical sample tube needs to be filtered.

[0003] Current technology uses a filter screen or membrane to filter bone marrow samples (if there are no ready-made filter screens, the filter cloth needs to be cut manually). A 300-mesh filter cloth (5-10 meters) is manually cut into small squares with sides of approximately 5cm (two people are needed to complete this operation each time), using 1-3 pieces per bone marrow sample. When filtering bone marrow samples, the sample tube cap is opened, and the entire bone marrow sample is drawn up using a 5ml Pasteur tube. The filter cloth is folded into a funnel shape and placed at the mouth of the test tube or sample tube. Bone marrow fluid is slowly dripped in, and the filter cloth is moved so that one side is close to the test tube mouth, allowing the bone marrow to pass through the filter cloth by its own gravity. This process is time-consuming and inefficient. Furthermore, during the slow dripping of bone marrow fluid, the sample is exposed to the outside environment for a long time, resulting in a large contact area and prolonged contact time with the non-sterile filter cloth, which easily leads to sample contamination. Current filtration methods take approximately 3-8 minutes per sample; if the sample exposure time exceeds 5 minutes, the risk of contamination increases by more than 30%. In addition, some bone marrow fluid samples are viscous and clog the filter cloth, preventing the bone marrow fluid from entering the sample tube smoothly by its own gravity. During the process of technicians changing the filter cloth and filtering again with the Pasteur tube, the bone marrow sticks to the replaced filter cloth, resulting in waste. Furthermore, careless operation can easily contaminate gloves or even cause occupational exposure.

[0004] Therefore, there is an urgent need to design a technical solution that has a short filtration time, high efficiency, and is less likely to cause sample contamination. Summary of the Invention

[0005] The purpose of this invention is to provide a bone marrow sample filtering device, sample tube, and filtering method to solve the problems existing in the prior art, so as to make the bone marrow sample filtering time short, efficient, easy to operate, and less likely to cause sample contamination.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a bone marrow sample filtering device, comprising: The annular filter holder has a sealing structure on its outer wall for sealing contact with the inner wall of the sample tube; A filter layer is fixedly disposed inside the annular filter frame and is used to filter bone marrow samples; The annular filter frame can move along the axial direction of the sample tube.

[0007] Preferably, the system further includes a support member, one end of which is fixedly connected to the top of the annular filter frame, and the support member is parallel to the axis of the sample tube.

[0008] Preferably, the support member includes a plurality of parallel support rods, one end of which is fixedly connected to the top of the annular filter frame, and the plurality of support rods are arranged circumferentially along the annular filter frame.

[0009] Preferably, the support further includes an annular positioning part, which has the same outer diameter as the annular filter frame and is coaxially arranged; the annular positioning part is fixedly connected to the end of the support rod away from the annular filter frame.

[0010] Preferably, the length of the support rod is less than the length of the sample tube.

[0011] Preferably, the filter layer includes a first filter screen and a second filter screen, which are stacked on the inner side of the annular filter frame, and the pore size of the first filter screen is larger than that of the second filter screen.

[0012] Preferably, the first filter screen has a pore size of 300 micrometers and is integrally formed with the annular filter frame. Its material is medical-grade plastic. In other embodiments, the first filter screen away from the second filter screen or the annular filter frame has burrs. These burrs are made of flexible rods of a certain length. During filtration, the burrs can block blood clots, preventing them from clogging the first filter screen and creating a gap between the blood clot and the filter screen. This allows bone marrow fluid to enter the filter screen through this gap, achieving filtration. In another embodiment, instead of burrs on the first filter screen, 5-7 integrally formed plastic tentacles are provided on the annular filter frame 1. These plastic tentacles extend downwards from the edge of the annular filter frame 1 and converge towards the center with a unique chrysanthemum-petal-like radial curved structure, forming a three-dimensional interception net. When a blood clot approaches, the plastic tentacles can firmly lock the blood clot using the bending tension, while bone marrow fluid can smoothly pass through the gap to reach the first and second filter screens.

[0013] Preferably, the pore size of the second filter screen is 50-100 micrometers.

[0014] The present invention also provides a sample tube, including a sample tube body and a bone marrow sample filtering device as described above. The bone marrow sample filtering device is inverted inside the sample tube body. A sample tube cap is detachably connected to the open end of the sample tube body. The annular filter frame of the bone marrow sample filtering device is connected to the inner side of the sample tube cap via a connecting rod.

[0015] The present invention also provides a filtration method for the bone marrow sample filtration device, comprising the following steps: Open the sample tube cap; The bone marrow sample filtering device is slowly inserted into the sample tube through the opening of the sample tube, keeping the annular filter frame and the sample tube wall in sealed contact, and the annular filter frame is pushed to the bottom position inside the sample tube. The sample tube cap is closed, and the silicone layer of the cap is pushed into the annular positioning part until the bone marrow sample filtering device is in close contact with the bottom of the sample tube. The bone marrow sample filtering device remains at the bottom of the sample tube, completing the filtration of the bone marrow sample solution in the sample tube.

[0016] The present invention achieves the following technical effects compared to the prior art: This invention features a double-layered filter within the inner space of a ring-shaped filter frame, forming a filtration device. The filtration device is pushed along the inlet of a sample tube containing bone marrow sample solution to the bottom of the tube, completing in-tube filtration of the bone marrow sample solution. Large particles are squeezed to the bottom of the tube after filtration, eliminating the need to aspirate the bone marrow fluid using a Pasteur tube. This invention achieves in-situ filtration within the sample tube, reducing filtration time to 10-15 seconds and sample exposure time by over 95%. This results in short filtration time, high efficiency, simple operation, and reduced risk of sample contamination and occupational exposure. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the bone marrow sample filtering device with burrs in Embodiment 1 of the present invention. Figure 2 for Figure 1 A magnified view of a portion of the image; Figure 3This is a schematic diagram of the bone marrow sample filtering device with plastic tentacles in Embodiment 1 of the present invention; Figure 4 for Figure 3 A magnified view of a portion of the image; Figure 5 This is a schematic diagram of the sample tube structure in Embodiment 2 of the present invention; Figure 6 for Figure 5 A schematic diagram of the decomposition process; Figure 7 for Figure 6 A magnified view of a portion of the image; Figure 8 This is a schematic diagram of the filtration method using a bone marrow sample filtration device with bristles in Embodiment 1 of the present invention. Figure 9 This is a schematic diagram of the filtration method using a bone marrow sample filtration device with plastic tentacles in Embodiment 1 of the present invention.

[0019] In the diagram: 1-ring filter frame, 101-sealing ring, 2-first filter screen, 201-burr, 202-plastic tentacles, 3-second filter screen, 4-support rod, 5-ring positioning part, 6-sample tube, 7-sample tube cap. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The purpose of this invention is to provide a bone marrow sample filtering device, sample tube, and filtering method to solve the problems existing in the prior art, so as to make the bone marrow sample filtering time short, efficient, easy to operate, and less likely to cause sample contamination.

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Existing technologies use filter screens or membranes to filter bone marrow. The filter cloth is folded into a funnel shape and placed at the mouth of a test tube or blood collection tube. Bone marrow fluid is slowly dripped in, and the filter cloth is moved so that one side is close to the test tube opening. The bone marrow then passes through the filter cloth and into the test tube or blood collection tube by its own gravity. This process is time-consuming and inefficient. Furthermore, during the slow dripping of bone marrow fluid, the sample is exposed to non-sterile filter cloth for an extended period, resulting in a large contact area and prolonged contact time, which easily leads to sample contamination. Some bone marrow fluid samples are viscous and can clog the filter cloth, preventing the bone marrow fluid from smoothly entering the test tube or blood collection tube by its own gravity. Changing the filter cloth and performing re-filtration with a Pasteur tube can also pose occupational exposure risks. To address these issues, this invention provides a bone marrow sample filtration device, referencing... Figure 1 As shown, the device includes an annular filter frame 1 and a filter layer. The outer wall of the annular filter frame 1 can be in sealed contact with the inner wall of the sample tube, and the annular filter frame 1 can move along the axial direction of the sample tube inside the sample tube. The filter layer is fixedly disposed inside the annular filter frame 1, which can shield the inner space of the annular filter frame 1 and cooperate with the annular filter frame 1 to divide the sample tube into upper and lower layers to achieve filtration of bone marrow sample solution. In one embodiment, the inner wall of the annular filter frame 1 is provided with an annular clamping groove, the filter layer is a circular sheet structure, and the outer edge of the filter layer is clamped in the annular clamping groove.

[0024] This invention features a filter layer within the inner space of a ring-shaped filter holder 1, forming a filter device. The bone marrow sample solution to be filtered is pre-placed in a sample tube. The filter device is then pushed along the inlet of the sample tube to the bottom, completing the in-tube filtration of the bone marrow sample solution. Large particles, blood clots, and fat particles are squeezed to the bottom of the sample tube. Pressure can be manually applied during the process to force the bone marrow fluid through the filter screen. The filter screen has a large area and features both coarse and fine layers, resulting in short filtration time and high efficiency. Furthermore, this filter device is a disposable sterile product, placed inside the sample tube for filtration, reducing the contact area and time between the bone marrow sample solution and the non-sterile filter cloth, thus minimizing sample contamination and occupational exposure.

[0025] Example 1 refer to Figure 1 , Figure 3As shown, a support member is designed in this embodiment. One end of the support member is fixedly connected to the top of the annular filter frame 1. The support member is parallel to the axis of the sample tube 6. During the filtration process, the support member is manually pushed into the sample tube 6 from the end away from the annular filter frame 1. This can realize the function of moving the annular filter frame 1 along the axial direction of the sample tube 6, thereby realizing the filtration process of the bone marrow sample solution in the sample tube 6. In one embodiment, the support member is made of multiple parallel support rods 4. One end of the support rod 4 is fixedly connected to the top of the annular filter frame 1. The multiple support rods 4 are arranged circumferentially along the annular filter frame 1. The annular filter frame 1 is placed at the opening of the sample tube 6. Then, the support rods 4 are used to push the annular filter frame 1 to the bottom of the sample tube 6, thereby realizing the function of pushing the annular filter frame 1 to the bottom of the sample tube 6.

[0026] To prevent the annular filter frame 1 from tilting during the filtration process, which could cause unfiltered bone marrow sample solution to flow between the annular filter frame 1 and the inner wall of the sample tube 6, an annular positioning part 5 is also designed in this embodiment. The annular positioning part 5 has the same outer diameter as the annular filter frame 1 and is coaxially arranged. The structure of the annular positioning part 5 is similar to that of the annular filter frame 1, and both are made of medical plastic or other medical materials. The difference is that the annular positioning part 5 does not have a filter layer and a sealing ring 101, and the width of the annular positioning part 5 is between 2-3 mm, that is, the difference between the inner diameter and the outer diameter of the annular positioning part 5 is between 2-3 mm. The annular positioning part 5 is fixedly connected to the end of the support rod 4 away from the annular filter frame 1. The annular positioning part 5 can drive the annular filter frame 1 to move axially along the sample tube 6 via the support rod 4, ensuring that the filtration device always moves axially along the sample tube 6 without tilting during the process. This ensures that the outer wall of the annular filter frame 1 is always in sealed contact with the inner wall of the sample tube 6 during the movement. In this embodiment, the length of the support rod 4 is less than the length of the sample tube 6, so that after the annular filter holder 1 enters the sample tube 6, the support rod 4 and the annular positioning part 5 also enter the sample tube 6. Then the sample tube 6 is placed on the blood cell counter for detection, or placed in the sample pretreatment equipment for subsequent processing.

[0027] To ensure a tight seal between the filter device and the inner wall of the sample tube 6, a sealing structure is designed. In a preferred embodiment, the sealing structure is a sealing ring 101 located in the groove on the outside of the annular filter frame 1. The sealing ring 101 is made of medical-grade silicone and has a compression rate of 20%-30%. The sealing ring 101 makes a sealing contact with the inner wall of the sample tube 6, thereby achieving a sealing function and preventing the bone marrow sample solution in the sample tube 6 from flowing out between the annular filter frame 1 and the inner wall of the sample tube 6 during the filtration process. This ensures that all the bone marrow sample solution in the sample tube 6 can be filtered through the filter layer.

[0028] Bone marrow samples often contain particulate matter such as fat droplets, hematopoietic cell clusters, and blood clots during collection and testing. Existing filtration devices mostly use a single filter structure, and these particles easily accumulate on the filter surface, causing blockages. This leads to increased filtration pressure and decreased efficiency. To reduce the impact on test results, the testing equipment needs to be shut down and the filter cleaned, wasting precious bone marrow samples and potentially delaying the testing process due to repeated shutdowns and cleaning. While some devices have attempted to increase the number of filter layers, they have not solved the core problem of deep-seated particle adhesion and blockage, still posing a risk of filtration interruption. To address this issue, in one embodiment, the filter layer is made of medical filter cloth or a medical filter screen, and its structure includes a first filter screen 2 and a second filter screen 3 arranged from bottom to top, such as... Figure 2 As shown, the first filter 2 and the second filter 3 are stacked on the inner side of the annular filter frame 1, and the pore size of the first filter 2 is larger than that of the second filter 3. In one embodiment, the pore size of the first filter 2 is 300 micrometers. The first filter 2 is integrally formed with the annular filter frame 1 and is made of medical plastic. The first filter 2 filters out small bone fragments and large connective tissue blocks. The second filter 3, with a pore size of 50-100 micrometers, filters out most non-hematopoietic cells such as osteoclasts, multinucleated giant cells, medium-sized adipocytes, and osteoblast clusters, as well as bone marrow particles, achieving stepwise impurity removal. The side of the first filter 2 away from the second filter 3 or the outer side of the annular filter frame 1 is provided with burrs 201 made of flexible material of a certain length to prevent blood clots from clogging the filter. The burrs are radially distributed and can pre-disperse the aggregated particles to prevent them from forming a large-area blockage layer.

[0029] like Figure 3 and Figure 4 As shown, in another embodiment of this invention, to further prevent blood clots from clogging the first filter screen 2, burrs 201 may not be provided on the first filter screen 2. Instead, 5-7 integrally formed plastic tentacles 202 may be provided on the annular filter frame 1. The plastic tentacles 202 extend downward from the edge of the annular filter frame 1 and converge towards the center with a unique chrysanthemum-petal-like radial curved structure, forming a three-dimensional interception net. When a blood clot approaches, the plastic tentacles 202 can firmly lock the blood clot with the bending tension, while the bone marrow fluid can smoothly pass through the gaps to reach the first filter screen 2 and the second filter screen 3. After receiving the sample tube 6, the bone marrow sample testing department opens the sample tube cap 7, inserts the bone marrow sample filtering device, and refers to... Figure 8 or Figure 9 To use the sample tube, push the bone marrow sample filter device to the bottom of the sample tube 6, then open the sample tube cap 7 again. Manually place the sample tube 6 on the fully automated blood analyzer for sample counting, or place it on the fully automated flow cytometry sample pretreatment device to complete subsequent flow cytometry sample pretreatment and detection operations.

[0030] Example 2 This embodiment is a further improvement upon Embodiment 1, with reference to... Figure 5 , Figure 6 and Figure 7 As shown, this embodiment provides a sample tube 6, including a sample tube body and a bone marrow sample filtering device. In this embodiment, the support rod of the bone marrow sample filtering device is fixedly connected to the sample tube cap 7 at the end furthest from the filter screen. The filter screen is arranged inverted. The sample tube cap 7 is integrally formed with the top of the support rod 4, or the sample tube cap 7 is fixedly connected to the top of the support rod 4 during factory production. When the bone marrow sample filtering device is located inside the sample tube 6, the sample tube cap 7 is sealed to the top opening of the sample tube 6. That is, in this embodiment, the first filter screen 2 is located near the tube opening, and the second filter screen 3 is located near the tube bottom. The sample tube cap 7 is detachably connected to the opening end of the sample tube body. The sample tube cap 7 can be snapped or threaded to the opening of the sample tube body. The bone marrow sample filtering device is connected to the inside of the sample tube cap 7 via a connecting rod. The tube contains a small amount of bone marrow sample. The pressure is negative, and the amount of heparin or EDTA-K2 anticoagulant is applied. In this embodiment, the 5 to 7 integrally formed plastic tentacles 202 set on the annular filter frame 1 are arranged in the opposite direction to the plastic tentacles 202 in the first embodiment. In this embodiment, the plastic tentacles 202 extend upward from the edge of the annular filter frame 1 and converge towards the center with a unique radial curved structure similar to chrysanthemum petals, forming a three-dimensional interception net. When the blood clot approaches, the plastic tentacles 202 can firmly lock the blood clot with the bending tension, while the bone marrow fluid can smoothly pass through the gap to reach the first filter screen 2 and the second filter screen 3. In this embodiment, when using the sample tube 6, a medical needle or similar device is used to inject the bone marrow sample solution into the sample tube 6 through the sample tube cap 7. The annular filter frame 1 and the tube wall of the sample tube 6 are kept in sealed contact. During injection, under the negative pressure inside the tube and the injection pressure, the bone marrow sample solution is filtered through the first filter screen 2 and the second filter screen 3 to the bottom of the sample tube 6. When a blood clot approaches, the plastic tentacle 202 can firmly lock the blood clot using bending tension, without interfering with the filtration of bone marrow fluid by the first filter screen 2 and the second filter screen 3. After receiving the sample, the laboratory personnel remove the sample tube cap 7 and the bone marrow sample filter device, and manually place the sample tube 6 on a fully automated blood analyzer for sample counting, or place it on a fully automated flow cytometry sample pretreatment device to complete subsequent flow cytometry sample pretreatment and detection operations.

[0031] Bone marrow filtration needs to be completed rapidly in a closed, sterile environment to avoid sample contamination and ensure cell viability. In existing devices, the assembly of the filter components and support structures often relies on threads or simple snap-fits, which are prone to positioning misalignment, leading to sample leakage or filtration path deviation during filtration, affecting filtration efficiency and sample purity. Some positioning structures are complex, inconvenient to disassemble and assemble, increasing operation time and the risk of contamination, making them unsuitable for rapid clinical testing needs. To avoid this problem, this embodiment features an annular positioning step on the upper inner side of the sample tube 6 of the filter device. A medical-grade silicone sealing ring is embedded in the step surface of the annular positioning step, forming a precise positioning and sealing integrated structure. The bottom of the filter component has a flange that matches the annular positioning step. The flange and the annular positioning step achieve rapid alignment through a conical surface fit, controlling assembly deviation within 0.1mm. A guide bevel is added to the edge of the annular positioning step, in conjunction with the scale markings on the sample tube 6, allowing for rapid alignment and installation of the filter component. This reduces assembly time by 60% compared to traditional structures while improving overall sealing.

[0032] Example 3 This embodiment provides a filtration method based on the bone marrow sample filtration device in Embodiment 1 above, referencing... Figure 8 and Figure 9 As shown, where, Figure 8 This corresponds to the method of using the bone marrow sample filtering device with the burr 201 structure in Embodiment 1. Figure 9 This corresponds to the method of using the bone marrow sample filtering device with the plastic tentacle 202 structure in Embodiment 1. The usage process is the same for both, including the following steps: Open the sample tube cap 7; The bone marrow sample filtering device is slowly and vertically inserted into the sample tube 6 through the opening of the sample tube 6, keeping the annular filter frame 1 and the tube wall of the sample tube 6 in sealed contact, until the annular positioning part 5 is fully inserted into the test tube. The sample tube 6 has been pre-injected with bone marrow sample solution through the sample tube cap 7, so the annular filter frame 1 can filter the bone marrow sample solution in the sample tube 6 as it moves along the axial direction of the sample tube 6.

[0033] The bone marrow sample filtering device does not need to be removed. The opening of sample tube 6 is sealed with the original sample tube cap 7. The sealing silicone layer inside the sample tube cap 7 can be squeezed and pushed into the annular positioning part 5, ensuring close contact between the bone marrow sample filtering device and the bottom of sample tube 6, thus completing the filtration of the bone marrow sample solution within sample tube 6. The filtered blood clots, connective tissue blocks, and bone marrow particles are squeezed to the bottom of sample tube 6, while the filtered solution is located at the upper part of sample tube 6.

[0034] By opening the sample tube cap 7, the sample tube 6 containing the filtration solution can be manually placed on a fully automated blood analyzer for sample counting, or placed on a fully automated flow cytometry sample pretreatment device to complete subsequent flow cytometry sample pretreatment and detection operations. The bone marrow sample filtration device of this invention is designed for single use only, eliminating the need for reuse and preventing cross-contamination at the source. Furthermore, it does not need to be removed after filtration, making it convenient to use. This device integrates a filter layer, annular filter frame 1, support rod 4, and annular positioning part 5 to achieve rapid filtration of bone marrow samples, making operation efficient and convenient. Its disposable design effectively prevents sample contamination and occupational exposure during the filtration process. The device reaches the bottom of the sample tube 6 without affecting subsequent sampling and testing, and can adapt to the needs of different equipment.

[0035] In another embodiment, the bone marrow sample filtration device can also be designed as a reusable structure. In this embodiment, the edge of the second filter screen 3 is provided with a micro-vibrating element, which, together with the dispersing effect of burrs, further reduces the clogging of particles in the filter screen pores and maintains the unobstructed filtration channel. The micro-vibrating element can be a micro motor or a micro-vibration motor, which can drive the second filter screen 3 to vibrate slightly. After filtration, the device can be cleaned and disinfected for the next use.

[0036] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A bone marrow sample filtering device, characterized in that: include: The annular filter holder has a sealing structure on its outer wall for sealing contact with the inner wall of the sample tube; A filter layer is fixedly disposed inside the annular filter frame and is used to filter bone marrow samples; The annular filter frame is movable along the axial direction of the sample tube; The filter layer includes a first filter screen and a second filter screen, which are stacked on the inner side of the annular filter frame, and the aperture of the first filter screen is larger than that of the second filter screen; the side of the first filter screen away from the second filter screen is provided with burrs.

2. The bone marrow sample filtering device according to claim 1, characterized in that: It also includes a support member, one end of which is fixedly connected to the top of the annular filter frame, and the support member is parallel to the axis of the sample tube.

3. The bone marrow sample filtering device according to claim 2, characterized in that: The support member includes a plurality of parallel support rods, one end of which is fixedly connected to the top of the annular filter frame, and the plurality of support rods are arranged circumferentially along the annular filter frame.

4. The bone marrow sample filtering device according to claim 3, characterized in that: The support member further includes an annular positioning part, which has the same outer diameter as the annular filter frame and is arranged coaxially; the annular positioning part is fixedly connected to the end of the support rod away from the annular filter frame.

5. The bone marrow sample filtering device according to claim 3, characterized in that: The length of the support rod is less than the length of the sample tube.

6. The bone marrow sample filtering device according to claim 1, characterized in that: The pore size of the first filter is 300 micrometers.

7. The bone marrow sample filtering device according to claim 1, characterized in that: The second filter has a pore size of 50-100 micrometers.

8. A sample tube, characterized in that: The sample tube includes a sample tube body and a bone marrow sample filtering device as described in any one of claims 1 to 7, wherein the bone marrow sample filtering device is inverted inside the sample tube body, a sample tube cap is detachably connected to the open end of the sample tube body, and the annular filter frame of the bone marrow sample filtering device is connected to the inside of the sample tube cap via a connecting rod.

9. A filtration method based on the bone marrow sample filtration device according to any one of claims 1 to 7, characterized in that: Includes the following steps: Open the sample tube cap; The bone marrow sample filtering device is slowly inserted into the sample tube through the opening of the sample tube, keeping the annular filter frame and the sample tube wall in sealed contact, and the annular filter frame is pushed to the bottom position inside the sample tube. The sample tube cap is closed, and the silicone layer of the cap is pushed into the annular positioning part until the bone marrow sample filtering device is in close contact with the bottom of the sample tube. The bone marrow sample filtering device remains at the bottom of the sample tube, completing the filtration of the bone marrow sample solution in the sample tube.

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