Liquid testing circuit and storage bag
The liquid test circuit with storage bags and adjustable tubes effectively maintains low shear stress for accurate plasma shear evaluation, addressing the challenge of assessing plasma component damage in blood compatibility testing.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- TOHOKU UNIV
- Filing Date
- 2025-12-12
- Publication Date
- 2026-06-18
AI Technical Summary
Existing liquid test circuits for blood compatibility testing face challenges in maintaining low shear stress conditions, particularly in evaluating plasma component damage due to shear stress, which is difficult to assess accurately.
A liquid test circuit design incorporating storage bags with pressure adjustment mechanisms and varying tube diameters to distribute pressure gradients, reducing localized shear stress and maintaining conditions suitable for plasma shear evaluation.
The design allows for accurate evaluation of plasma shear stress under low shear conditions, enabling effective assessment of plasma component damage and reducing the risk of von Willebrand syndrome.
Smart Images
Figure JP2025043555_18062026_PF_FP_ABST
Abstract
Description
Liquid test circuit and storage bag 【0001】 The present invention relates to a liquid test circuit and a storage bag. 【0002】 Conventionally, in the treatment of severe heart failure and vascular diseases and during their surgical operations, it is known that systems that replace the blood pumping function, such as blood pumps and auxiliary circulation devices, and implantable artificial organs are used. As a blood compatibility test for these devices (blood pumps, auxiliary circulation devices, etc.) composed of artificial materials to confirm that they do not cause excessive damage to blood cells, for example, a hemolysis test defined by the American Society for Testing and Materials standards (ASTM-F1841, etc.) is performed (see Non-Patent Document 1). 【0003】 Richard Malinauskas,Luke Herbertson,Jean Rinaldi,Megan Jamiolkowski,Qijin Lu, In Vitro Dynamic Hemolysis Testing of BloodPumps:Updating the ASTM F1841 Testing Standard,FDA / Center for Devices and Radiological Health(CDRH) / Office of Science and Engineering Laboratories(OSEL),[Search Date 2024.12.03], Internet <URL:https: / / www.fda.gov / media / 149239 / download> 【0004】 However, in the test circuit defined by the above standards (ASTM-F1841, etc.), the shear stress in the test circuit is high, and it is difficult to evaluate the damage to plasma components caused by shear stress due to the test object, such as the shear evaluation of von Willebrand factor. The present invention has been made in view of such circumstances, and its object is to provide a technology for a liquid test circuit capable of maintaining the shear stress in the test circuit in a low shear region. 【0005】 The inventors of the present invention have intensively studied and found that the following configuration can solve the above problems in the liquid test circuit. 【0006】In other words, the configuration of the present invention is as follows: [1] A liquid test circuit comprising: a pump that delivers the liquid sample introduced from a first side of a circuit through which the liquid sample circulates to a second side; a first tube that forms the circuit and has one end connected to the second side of the pump; a first storage bag connected to the other end of the first tube, having an inlet into which the liquid sample flows and an outlet outlet into which the liquid sample flows out, storing the liquid sample flowing in from the inlet and having an adjustment mechanism for adjusting the pressure of the liquid sample circulating in the circuit; and a second tube, one end connected to the outlet outlet of the first storage bag and the other end connected to the first side of the pump. [2] The liquid test circuit according to [1], further comprising: a second storage bag having an inlet connected to the other end of the second tube and an outlet connected to the first side of the pump, which stores the liquid sample flowing in from the inlet and has an adjustment mechanism for adjusting the pressure of the liquid sample circulating in the circuit and flowing out from the outlet. [3] The liquid test circuit according to [1] or [2], wherein the first tube has a diameter larger than the diameter of the second tube. [4] The liquid test circuit according to [1], wherein the second tube has a 2-1 tube portion and a 2-2 tube portion having a different diameter from the 2-1 tube, one end of the 2-1 tube portion is connected to the outlet of the first storage bag, the other end is connected to one end of the 2-2 tube portion, and the other end of the 2-2 tube portion is connected to the first side of the pump. [5] The liquid test circuit according to [2], wherein the second tube has a second-first tube portion and a second-second tube portion having a different diameter from the second-first tube, one end of the second-first tube portion is connected to the outflow portion of the first storage bag, the other end is connected to one end of the second-second tube portion, and the other end of the second-second tube portion is connected to the inflow portion of the second storage bag. [6] The liquid test circuit according to [1] or [2], wherein the first tube and the second tube are configured with the same diameter.[7] A storage bag having an inlet for into which a liquid sample flows in and an outlet for which the liquid sample flows out, and comprising an adjustment mechanism for storing the liquid sample flowing in from the inlet and for adjusting the volume of the stored liquid sample. 【0007】 According to the present invention, a technology for a liquid test circuit capable of maintaining shear stress in a low shear region within the test circuit can be provided. 【0008】 Figure 1 shows a schematic configuration of a liquid test circuit as a comparative example. Figure 2 shows a schematic configuration of a liquid test circuit according to Example 1. Figure 3 shows a schematic configuration of a liquid test circuit according to Example 2. Figure 4 is a diagram illustrating the plasma shear stress test using the liquid test circuit of Example 2. Figure 5 shows an example of a sample obtained by the plasma shear stress test of Example 2. 【0009】 Hereinafter, with reference to the drawings, one embodiment for carrying out the invention (hereinafter also referred to as "one embodiment" or "embodiment") will be described. The configuration of the following embodiment is illustrative, and the configuration of the liquid test circuit disclosed in this embodiment may be appropriately changed depending on the liquid sample to be analyzed. Unless otherwise specified, the configurations disclosed in this embodiment are not intended to limit the technical scope of the invention to only those configurations, and can be combined as much as possible. 【0010】 Furthermore, the drawings referenced in the following description merely provide a schematic representation of the shape, size, and positional relationships to the extent necessary to understand the content of the present invention. In other words, the present invention is not limited to the shapes, sizes, and positional relationships exemplified in each drawing. Also, there may be parts where the dimensional relationships and ratios differ between drawings. 【0011】 [Embodiments] (Comparative Example) Before describing the liquid test circuit and storage bag according to this embodiment, a comparative example liquid test circuit will be described. Figure 1 is a diagram showing the schematic configuration of a liquid test circuit 100 as a comparative example. Figure 1 illustrates the schematic of a liquid test circuit 100 that constitutes a typical blood flow loop for testing an extracorporeal or implantable blood pump as specified in the American Society for Testing and Materials standard (ASTM-F1841). 【0012】 The liquid test circuit 100 includes a storage container 103 having a space 104 for storing the blood (liquid sample) to be tested, a blood pump 101 for sending the blood introduced on the inlet side to the outlet side, and tubes 102-1 and 102-2. One end of tube 102-1 is connected to the outlet side of the blood pump 101, and the other end is connected to the inlet of the storage container 103. One end of tube 102-2 is connected to the outlet side of the storage container 103, and the other end is connected to the inlet side of the blood pump 101. A predetermined volume of blood injected through the inlet is stored in the space 104 of the storage container 103. 【0013】 In the liquid test circuit 100, the blood stored in the space 104 of the storage container 103 flows into the inlet side of the blood pump 101 through the tube 102-2 connected to the outlet. The blood that flows into the blood pump 101 is driven by the pump and sent to the outlet side, and flows into the inlet side of the storage container 103 through the tube 102-1 connected to the outlet side of the blood pump 101. In the liquid test circuit 100, a circulatory path (blood flow loop) for blood compatibility testing of devices used for circulatory support, etc., is formed through the storage container 103, tube 102-2, blood pump 101, and tube 102-1, as indicated by the direction of the white arrow in Figure 1. 【0014】 In blood compatibility testing of devices used for circulatory support, etc., for example, the storage capacity of the storage container 103 is set to "450 ml" and the blood flow rate through the blood flow loop is set to "5 L / min" for the blood compatibility test (hemolysis test). In the blood compatibility test, various ports, sensors, and adjustment mechanisms for evaluating the degree of damage to the blood under test are provided in the blood flow loop of the liquid test circuit 100. For example, a sampling port 106 for periodically (for example, every hour) collecting blood flowing through the blood flow loop and a measurement port 107-2 for measuring the pressure (Pin) on the inflow side of the blood pump 101 are provided in the tube 102-2. In addition, the tube 102-2 is provided with a sensor 107-1 for measuring the flow rate of blood flowing through the blood flow loop and a temperature adjustment mechanism 105 such as a constant temperature bath for adjusting the blood temperature to a certain range. 【0015】Tube 102-1 is provided with a measurement port 107-3 for measuring the pressure (Pout) on the outlet side of the blood pump 101, and a measurement port 107-4 for measuring the temperature of the blood flowing through the blood flow loop. Tube 102-1 is also provided with a tube clamp 108 for adjusting the pressure of the blood flowing through the blood flow loop. The tube clamp 108 allows for the creation of a constricted section formed by tube 102-1 within the liquid test circuit, thereby changing the pipeline resistance and generating physiological or assisted circulation pressure. 【0016】 The pressure values measured via measurement ports 107-2 and 107-3, and the flow rate values measured via sensor 107-1, allow the pressure-flow characteristics of the blood pump 101 during the hemolysis test to be adjusted hemodynamically to be equivalent to those of biological blood circulation and when using an auxiliary circulatory device. Similarly, the temperature range measured via measurement port 107-4 and the temperature adjustment mechanism 105 allow the temperature environment during the hemolysis test to be adjusted hemodynamically to be equivalent to those of biological blood circulation and when using an auxiliary circulatory device. 【0017】 During the hemolysis test, the volume of blood flowing through the blood flow loop formed by the liquid test circuit 100 decreases each time a sample of blood is collected via the collection port 106. The liquid test circuit 100 is configured to maintain the pressure-flow characteristics before and after the decrease in the volume of blood flowing through the blood flow loop by changing the pipeline resistance of the blood flowing through the tube 102-1 through pressure adjustment via the tube clamp 108. 【0018】Thus, the liquid test circuit 100 is configured to generate physiological and assisted circulation pressure by changing the tubing resistance of the blood flowing through the blood flow loop via a tube clamp 108 provided on the tube 102-1 connected to the output side of the blood pump 101. However, in the comparative example liquid test circuit 100, when the volume of blood in the liquid test circuit decreases, the inflow-outflow pressure difference increases with the increase in flow rate of the blood pump 101, resulting in negative pressure due to a decrease in pressure on the inflow side. When negative pressure occurs due to a decrease in pressure on the inflow side, the load on the blood flowing in and out of the blood pump 101 increases locally. As a result, in the comparative example liquid test circuit 100, the shear stress in the liquid test circuit increases, making it difficult to evaluate plasma component damage caused by shear stress due to the test material, such as the shear evaluation of the von Willebrand factor. 【0019】 Furthermore, it has been suggested that plasma protein damage due to shear stress in the blood can occur even in low-shear regions, unlike red blood cell damage which is a hemolytic phenomenon, and since this can lead to acquired von Willebrand syndrome, reducing the shear stress in liquid test circuits is a technical challenge. In this embodiment, for plasma shear stress testing due to blood shear related to devices such as blood pumps and circulatory support devices, a liquid test circuit capable of maintaining the shear stress within the test circuit in a low-shear region is realized. 【0020】(Example 1) Figure 2 is a diagram showing the schematic configuration of a liquid test circuit 10 according to Example 1. The liquid test circuit 10 according to Example 1 (hereinafter also referred to as the "test circuit") comprises storage bags 15 and 16, a centrifugal blood pump 11, tubes 12-1 and 12-2, and a resistance tube 13 that generates pressure during physiological or assisted circulation. One end of tube 12-1 is connected to the outlet side of the blood pump 11, and the other end is connected to the inlet of the storage bag 15. One end of tube 12-2 is connected to the outlet side of the storage bag 15, and the other end is connected to one end of the resistance tube 13. The other end of the resistance tube 13 is connected to the inlet of the storage bag 16, and the outlet of the storage bag 16 is connected to the inlet side of the blood pump 11. In this embodiment, including Examples 1 and 2 and its modifications, the inlet side of the blood pump is an example of the "first side", and the outlet side is an example of the "second side". Furthermore, tube 12-1 in Example 1 and tube 12 in Example 2 are examples of "first tubes," while tube 12-2 in Example 1, resistance tube 13, and resistance tube 13 in Example 2 are examples of "second tubes." Also, storage bag 15 is an example of a "first storage bag," and storage bag 16 is an example of a "second storage bag." 【0021】 In the test circuit 10 according to Example 1, the blood stored in the storage bag 15 flows into the inlet of the storage bag 16 through the tube 12-2 and the resistance tube 13 connected to the outflow section. The blood that flows into the storage bag 16 flows into the input side of the blood pump 11 through the outflow section. The blood that flows into the blood pump 11 is driven by the pump and sent to the outflow side, and flows into the inlet of the storage bag 15 through the tube 12-1. In the test circuit 10 of Example 1, a circulatory path (blood flow loop) for blood compatibility testing of devices used for circulatory support, etc., is formed through the storage bag 15, tube 12-2, resistance tube 13, storage bag 16, blood pump 11, and tube 12-1. In the blood compatibility test (hemolysis test), various ports, sensors, and adjustment mechanisms for evaluating the degree of damage to the blood under test are provided in the blood flow loop of the test circuit 10, similar to the comparative example. 【0022】Figure 2 illustrates a measurement port 17-3 provided at the connection point 14 between the outflow section of the storage bag 16 and the input side of the blood pump 11, for measuring the pressure (Pin) on the inflow side of the blood pump 11. Also illustrated are a measurement port 17-2 provided on the tube 12-1 for measuring the pressure (Pout) on the outflow side of the blood pump 11, and a sensor 17-1 for measuring the flow rate of blood flowing through the blood flow loop. Ports for periodically (for example, every 30 minutes) collecting blood flowing through the blood flow loop can be appropriately provided on, for example, the tube 12-2. 【0023】 As described above, the test circuit 10 according to Embodiment 1 is configured to include a storage bag 16 connected to the inlet of the blood pump 11 and a storage bag 15 connected to the outlet of the blood pump 11 via tube 12-1. The storage bag 16 is positioned near the inlet side of the blood pump 11. The diameter of the resistance tube 13 is configured to be smaller than the diameters of tubes 12-1 and 12-2. The storage bags 15 and 16 according to Embodiment 1 are configured to include adjustment mechanisms 15-1 and 16-1 for adjusting the pressure of the blood circulating in the test circuit 10. Hereafter, "tube diameter" will refer to the "inner diameter" of the various tubes. 【0024】 The adjustment mechanism 15-1 has a structure that allows adjustment of the stored volume by sandwiching the space for storing blood in the storage bag 15 between two plates that can be pressurized by fastening screws or the like. The same applies to the adjustment mechanism 16-1. However, the structure of the adjustment mechanisms 15-1 and 16-1 is not limited to these. An appropriate structure can be adopted depending on the properties and characteristics of the liquid sample to be tested, the amount of liquid flowing through the test circuit 10, etc. 【0025】 In Example 1, by providing storage bags 15 and 16 having adjustment mechanisms 15-1 and 16-1 and capable of volume adjustment, the decrease in circuit pressure due to the decrease in circuit volume caused by blood samples collected over time can be adjusted to match the test conditions. In the test circuit 10 according to Example 1, the load on the blood can be set to a constant condition. 【0026】Furthermore, in Example 1, for example, by setting the diameter of tubes 12-1 and 12-2 to 3 / 8 inch and the diameter of resistance tube 13 to 1 / 4 inch, it becomes possible to adjust the pressure load of the blood pump 11 by a distributed pressure gradient generated in the tube section with a reduced diameter. In Example 1, tube 12-2 corresponds to the "second-first tube section," and resistance tube 13 corresponds to the "second-first tube section." In the test circuit 10 according to Example 1, there is no increase in shear stress concentrated locally, and it becomes possible to maintain the shear stress of the circuit in the low shear region. In Figure 2, the length of resistance tube 13 is set to 50 cm, but it is preferable to make the length of the tube as short as possible. This is because the pipeline resistance increases with the length of the tube. If the pressure can be adjusted by the storage bag 15 and the generation of negative pressure in the pump can be suppressed, the storage bag 16 may not be necessary. 【0027】 (Evaluation Test) An evaluation test was conducted to assess the pressure on the inlet side (Pin) and the outlet side (Pout) of the blood pump 11, with the volume of blood flowing through the blood flow loop of the test circuit 10 shown in Figure 2 set to "400 mL". The rotation speed (rpm) of the centrifugal blood pump 11 in the evaluation test was set to three patterns: "2000", "2500", and "3000". The flow rate values (L / min) of the blood flowing through the blood flow loop, measured by the sensor 17-1 installed on the tube 12-1, were "4.0", "5.1", and "6.2", in the order of the above rotation speeds. 【0028】 The inflow pressure (Pin) of the blood pump 11 was measured through a measurement port 17-3 provided at the connection port 14 between the outflow port of the storage bag 16 and the blood pump 11, and the outflow pressure (Pout) of the blood pump 11 was measured through a measurement port 17-2 provided at the tube 12-1. The measurement results showed that the inflow pressure (Pin / mmHg) was "5", "5", and "5" in the order of the rotation speeds mentioned above. The outflow pressure (Pout / mmHg) was measured at "95", "144", and "202" in the order of the rotation speeds mentioned above. 【0029】For three rotational speeds of the blood pump 11, the measured inflow pressure (Pin) was "5 / mmHg" in all cases, confirming that no negative pressure was generated due to a drop in inflow pressure. Furthermore, for the three rotational speeds of the blood pump 11, the measured outflow pressure (Pout / mmHg) varied to "95," "144," and "202," indicating that although the inflow-outflow pressure difference increased, the inflow pressure (Pin) could be maintained within a predetermined range. The liquid test circuit 10 according to this embodiment provides a technology that can maintain shear stress in the test circuit within a low shear region. 【0030】 (Example 2) According to ASTM-F1841, blood compatibility tests specified by international standards generally require a circuit volume equivalent to or exceeding the amount of blood collected during human blood donation (400 mL). However, when conducting experiments with human blood, there is a limit to the amount of blood that can be collected at one time, making it difficult to perform multiple tests using the same blood. Therefore, reducing the volume of the liquid test circuit and conducting the test under blood flow conditions that match physiological blood pressure and blood flow is also a challenge. In the liquid test circuit 10 according to Example 2, a liquid test circuit 10 is realized that allows for a reduced volume and testing under blood flow conditions that match physiological blood pressure and blood flow for plasma shear stress testing. 【0031】 Figure 3 shows a schematic configuration of the liquid test circuit (hereinafter also referred to as the "test circuit") 10 according to Embodiment 2. The test circuit 10 according to Embodiment 2 comprises storage bags 15 and 16, a centrifugal blood pump 11, a tube 12, and a resistance tube 13. One end of the tube 12 is connected to the outlet side of the blood pump 11, and the other end is connected to the inlet of the storage bag 15. One end of the resistance tube 13 is connected to the outlet side of the storage bag 15, and the other end is connected to the inlet of the storage bag 16. The outlet side of the storage bag 16 is connected to the inlet side of the blood pump 11. 【0032】The test circuit 10 according to Example 2 differs from the test circuit 10 according to Example 1 in that it includes storage bags 15 and 16 with a storage capacity of 200 mL, and tubes 12 and resistance tubes 13 of the same diameter. The storage bags 15 and 16 are equipped with adjustment mechanisms 15-1 and 16-1 for adjusting the pressure of the blood circulating in the test circuit 10, similar to Example 1. Furthermore, in the test circuit 10 shown in Figure 2, an example is provided in which the tubes 12 and resistance tubes 13 have a diameter of 1 / 4 inch. 【0033】 In the test circuit 10 according to Embodiment 2, the blood stored in the storage bag 15 flows into the inlet of the storage bag 16 through the resistance tube 13 connected to the outlet. The blood that flows into the storage bag 16 flows to the input side of the blood pump 11 through the outlet. The storage bag 16 is positioned near the inlet side of the blood pump 11. The blood that flows into the blood pump 11 is driven by the pump and sent to the outlet side, and flows into the inlet of the storage bag 15 through the tube 12. In the test circuit 10 of Embodiment 2, a circulatory path (blood flow loop) for blood compatibility testing of devices used for circulatory support, etc., is formed through the storage bag 15, resistance tube 13, storage bag 16, blood pump 11, and tube 12. 【0034】 In the configuration shown in Figure 3, a measurement port 17-3 for measuring the pressure (Pin) on the inlet side of the blood pump 11 is provided at the connection port 14 between the outlet of the storage bag 16 and the input side of the blood pump 11. A measurement port 17-2 for measuring the pressure (Pout) is provided on the outlet side of the blood pump 11, and a sensor 17-1 for measuring the flow rate of blood flowing through the blood flow loop is provided at the outlet of the storage bag 15. A port for periodically (for example, every 30 minutes) collecting blood flowing through the blood flow loop is appropriately provided, for example, on a resistance tube 13. 【0035】 In Example 2, the storage bags 15 and 16 are equipped with adjustment mechanisms 15-1 and 16-1, allowing for volume adjustment and enabling adjustment of the decrease in circuit pressure due to the decrease in circuit volume caused by blood samples collected over time to match the test conditions. In the embodiment of Example 2, the test circuit 10 can also be configured to maintain a constant load on the blood. 【0036】 (Evaluation Test) Figure 4 illustrates the plasma shear stress test using the test circuit 10 of Example 2. The plasma shear stress test was performed with a blood volume of "200 mL" flowing through the blood flow loop of the test circuit 10, a flow rate of "4 L / min", and a rotation speed of "3000 rpm" for the centrifugal blood pump 11. Samples for the plasma shear stress test were taken according to a predetermined sampling schedule (0, 30, 60, 90, 120, 150, 180 / min). In the plasma shear stress test, after sample acquisition, the volumes of the storage bags 15 and 16 were adjusted as appropriate to maintain the inflow pressure of the blood pump 11 within a certain range (for example, 5 mmHg). 【0037】 As shown in Figure 4, in the plasma shear stress test, the storage bag 16, which is placed near the blood pump 11, is immersed in a constant temperature bath 18 to maintain the blood temperature within a certain range. The storage bag 15, which is connected to the output side of the blood pump 11 via a tube 12, is configured to be suspended at a higher position than where the blood pump 11 and storage bag 16 are located. By placing the storage bag 15 at a higher position than where the blood pump 11 and storage bag 16 are located, the outflow load of the blood pump 11 can be increased by potential energy. 【0038】As a result of the plasma shear stress test using the test circuit 10 of Example 2, plasma free hemoglobin samples shown in Figure 5 were obtained. Samples Z1 to Z7 represent samples taken at "0 min", "30 min", "60 min", "90 min", "120 min", "150 min", and "180 min", respectively. By measuring the concentration of plasma free hemoglobin and examining von Willebrand multimer deficiency in each sample taken in the plasma shear stress test, it was confirmed that mechanical hemolysis caused by devices used for circulatory support, etc., can be evaluated under certain conditions. The liquid test circuit 10 of Example 2 made it possible to perform plasma shear stress tests under blood flow conditions that match physiological blood pressure and blood flow rates with reduced volume, and it was confirmed that von Willebrand factor can also be evaluated over time. Furthermore, the reduced-volume liquid test circuit 10 of Example 2 is expected to be applicable to in vivo tests targeting the blood and plasma of animals such as goats. 【0039】 (Modified Version) As a modified version of the liquid test circuit, for example, the storage bag 16 located near the blood pump 11 in the liquid test circuit 10 described in Examples 1 and 2 may be omitted. That is, the modified liquid test circuit may be a configuration comprising a storage bag 15, a blood pump 11, tubes 12-1, 12-2, and a resistance tube 13, or a configuration comprising a storage bag 15, a blood pump 11, tube 12, and a resistance tube 13. Even in such a configuration, the storage bag 15 can be adjusted in volume by the adjustment mechanism 15-1, so that the decrease in circuit pressure due to the decrease in the circuit contents due to blood samples collected over time can be adjusted to match the test conditions. In the modified version, a liquid test circuit capable of evaluating plasma shear load with a simplified circuit configuration can be provided. 【0040】 10. Liquid test circuit 11. Blood pump 12. 12-1, 12-2. Tubing 13. Resistance tubing 14. Connection 15. 16. Storage bag 15-1, 16-1. Adjustment mechanism 17-1, 17-3. Measurement port 17-2. Sensor 18. Constant temperature bath
Claims
1. A liquid test circuit characterized by comprising: a pump that delivers a liquid sample introduced from a first side of a circuit through which a liquid sample circulates to a second side; a first tube that forms the circuit and has one end connected to the second side of the pump; a first storage bag connected to the other end of the first tube, having an inlet into which the liquid sample flows and an outlet outlet into which the liquid sample flows out, storing the liquid sample flowing in from the inlet and having an adjustment mechanism for adjusting the pressure of the liquid sample circulating in the circuit; and a second tube, one end connected to the outlet outlet of the first storage bag and the other end connected to the first side of the pump.
2. The liquid test circuit according to claim 1, further comprising: a second storage bag having an inlet connected to the other end of the second tube and an outlet connected to the first side of the pump, which stores the liquid sample flowing in from the inlet and has an adjustment mechanism for adjusting the pressure of the liquid sample circulating in the circuit and flowing out from the outlet.
3. The liquid test circuit according to claim 1 or 2, wherein the first tube has a diameter larger than the diameter of the second tube.
4. The liquid test circuit according to claim 1, wherein the second tube has a second-first tube portion and a second-second tube portion having a different diameter from the second-first tube, one end of the second-first tube portion is connected to the outlet of the first storage bag, the other end is connected to one end of the second-second tube portion, and the other end of the second-second tube portion is connected to the first side of the pump.
5. The liquid test circuit according to claim 2, wherein the second tube has a second-first tube portion and a second-second tube portion having a different diameter from the second-first tube, one end of the second-first tube portion is connected to the outflow portion of the first storage bag, the other end is connected to one end of the second-second tube portion, and the other end of the second-second tube portion is connected to the inflow portion of the second storage bag.
6. The liquid test circuit according to claim 1 or 2, wherein the first tube and the second tube are made up of the same diameter.
7. A storage bag having an inlet for into which a liquid sample flows in and an outlet for which the liquid sample flows out, and comprising an adjustment mechanism for storing the liquid sample flowing in from the inlet and for adjusting the volume of the stored liquid sample.