Automated analyzing device and abnormality determining method for same

Abstract

In order to provide an automated analyzing device capable of easily and accurately detecting an abnormality occurring during a liquid dispensing operation, the following configuration is adopted.　Provided are an automated analyzing device and an abnormality determining method for the same, the automated analyzing device comprising: a probe that performs a dispensing operation including a process for sucking and / or discharging a liquid; a syringe that generates pressure fluctuations for dispensing the liquid using the probe; a flow path connecting the probe and the syringe; a sensor for measuring a pressure in the flow path when the liquid is being dispensed; a calculating unit for calculating an attenuation rate of a time-varying waveform of the pressure measured by the sensor after a predetermined operation of the syringe; and a determining unit for determining whether an abnormality has occurred in the process during the dispensing of the liquid, on the basis of the attenuation rate calculated by the calculating unit.

Description

Automatic analyzer and method for determining abnormality thereof

[0001] The present invention relates to an automatic analyzer that performs qualitative and quantitative analysis of components in biological samples such as blood and urine, and in particular to an automatic analyzer that can more accurately detect the occurrence of abnormal dispensing, such as the unintentional aspirating of air during sample aspiration, a so-called "empty aspiration."

[0002] An automated analyzer is a device that reacts a biological sample, such as blood, with the components to be measured in the sample and an analytical reagent, and detects the reaction using optical techniques.It automatically performs all processes, from detecting the components to be measured to outputting the results.

[0003] Automated analyzers have become one of the necessary devices for efficient analysis in laboratory centers and other medical research facilities that contract out sample testing / examination to hospitals and clinics.

[0004] A typical automated analyzer is equipped with a specimen dispensing mechanism for dispensing a sample to be measured. The specimen dispensing mechanism includes a dispensing probe (sometimes called a dispensing nozzle; hereinafter referred to as the probe), a syringe connected to the dispensing probe, and a mechanism for moving the probe to a predetermined position. The mechanism performs a liquid dispensing operation, such as aspirating a predetermined amount of liquid into the probe by driving the syringe with the tip of the probe inserted into the liquid, and discharging the liquid from the probe by driving the syringe when the probe is in the dispensing position, thereby transferring the liquid from one container to another.

[0005] In order to prevent contamination caused by mixing of different aspirated liquids, a disposable tip may be attached to the tip of the probe when dispensing the liquid.

[0006] However, when handling liquid during dispensing operations, there are cases where the probe tip is positioned above the liquid surface and the liquid is aspirated, resulting in the unintentional aspirating of air or bubbles instead of the intended liquid. In such a situation, if the required amount of liquid is not aspirated, accurate analysis results cannot be obtained.

[0007] Furthermore, if such a situation goes unnoticed and the analytical results obtained are used for diagnosis, there is a concern that an accurate diagnosis may not be possible. Therefore, it is important in clinical testing to accurately determine whether or not such an abnormality has occurred.

[0008] As a means for solving such problems, Patent Document 1 discloses a technology in which pressure fluctuations are sampled at regular intervals, triggered by a so-called backlash correction operation, which is a process in which the motor that drives the syringe cancels out play in the gear that drives the syringe, and the pressure integral value over a certain time interval is calculated and compared with a threshold value set in advance for each dispensing amount as a judgment value, thereby distinguishing between normal aspiration and aspiration when air bubbles are present.

[0009] JP 2009-058318 A

[0010] The method of focusing on the pressure integral value over a time interval of the pressure inside the dispensing channel during liquid ejection, as in Patent Document 1, can effectively detect abnormalities when a relatively large difference is observed in the pressure waveform within the integral interval, but it may be difficult to detect abnormalities when the amount of sample dispensed is small and no large difference is observed in the pressure waveform within the integral interval between normal and abnormal conditions.

[0011] It is also expected that the integration interval will need to be adjusted depending on the dispensed amount, and the increase in parameters used for judgment is likely to increase the calculation load and required time.

[0012] In view of the above problems, an object of the present invention is to provide an automatic analyzer that can easily detect abnormal dispensing with high accuracy.

[0013] The present invention has the following configuration for solving the above problems.

[0014] An automatic analyzer comprising: a probe that performs dispensing operations including suction and / or discharge processes for a liquid; a syringe that generates pressure fluctuations to dispense the liquid with the probe; a flow path that connects the probe and the syringe; a sensor that measures the pressure in the flow path when dispensing the liquid; a calculation unit that calculates the attenuation rate of a time-varying waveform of the pressure measured by the sensor after a predetermined operation of the syringe; and a determination unit that determines whether or not there was an abnormality in the process of dispensing the liquid based on the attenuation rate calculated by the calculation unit.

[0015] Here, typical examples of liquids are reagents and specimens (samples), but the present invention can be applied to any liquid that requires dispensing in a predetermined amount.

[0016] A probe can be any mechanism that temporarily holds a predetermined amount of liquid and transfers the liquid from one container to another. This term is not intended to be limiting. For example, some devices use the term "sipper nozzle," but this is also included in the concept of a probe.

[0017] A syringe is a typical example of a pressure generating source in which a piston-shaped mechanical part is driven by a driving mechanism such as a motor via a gear, but regardless of the name, any device that can generate pressure fluctuations, such as a gear pump or rotor pump, can be used.

[0018] The present invention provides an automatic analyzer capable of easily and accurately detecting abnormalities in dispensing. Please refer to the descriptions in the respective examples for the effects of the individual embodiments.

[0019] Schematic diagram of an automatic analyzer. Schematic diagram of the sample dispensing mechanism of an automatic analyzer. Diagram showing fluid movement within the sample probe from the liquid aspirating operation of the sample probe to the backlash dispensing operation (a) During normal aspirating (b) During empty aspirating (c) When liquid and air are aspirated. Diagram showing pressure fluctuations within the dispensing flow path during (a) sample aspirating (b) during backlash dispensing. Illustrates the pressure waveform and decay rate calculation during backlash dispensing (a) Diagram showing maximum value, minimum value, and period (b) Diagram showing baseline and amplitude. Diagram showing the results of the decay rate calculation for the amount of liquid aspirated. Diagram showing the flow of the dispensing operation and pressure judgment. Diagram showing the relationship between the ratio of the actual aspirated amount to the set aspirated amount and the decay rate.

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in this specification. Furthermore, in all drawings used to explain the present invention, parts having the same function are designated by the same reference numerals, and repeated explanations thereof may be omitted.

[0021] FIG. 1 is a diagram showing an example of the configuration of an automatic analyzer according to the present invention.

[0022] Sample containers 103 can be placed in a ring shape on a sample disk 102 inside an automatic analyzer 101. When dispensing a sample, the disk rotates clockwise and counterclockwise, moving the sample containers 103 to an access position of a sample dispensing mechanism 104.

[0023] To simplify sample management, an identification barcode may be attached to the sample container 103. The barcode records information linked to the sample ID and information related to the sample type (e.g., serum, urine, etc.). The barcode attached to the sample container 103 is read by a barcode reader 120.

[0024] The sample dispensing mechanism 104 is composed of a rotation drive mechanism, a vertical drive mechanism, and a dispensing probe. The rotation drive mechanism and the vertical drive mechanism move the sample dispensing mechanism between a sample suction position and a sample dispensing position.

[0025] The reagent storage cabinet 105 has a reagent disk 106 and reagent container holders 107. Reagent storage cabinets generally have a cooling function to prevent reagents from deteriorating over time. The reagent container holders 107 are arranged in a double ring on the reagent disk 106 and are designed to hold multiple reagent bottles. The reagent disk 106 has a rotation drive mechanism, and by rotation, each reagent bottle is moved to a predetermined position on the circumference.

[0026] The automated analyzer of the present invention is equipped with a reagent dispensing mechanism 108 for biochemical analysis. The reagent dispensing mechanism 108 is composed of a rotation drive mechanism, a vertical drive mechanism, and a dispensing probe. The reagent dispensing mechanism rotates and descends to the position of a predetermined type of reagent bottle on the reagent disk 106, and aspirates a predetermined amount of reagent. After aspirating the reagent, the dispensing mechanism ascends. Next, it rotates and descends to the reagent ejection destination (a predetermined reaction cell on the reaction disk 109), and ejects the reagent.

[0027] The flow of biochemical analysis will be explained in the order of processing (sample dispensing, reagent dispensing, reaction, and detection).

[0028] First, the specimen dispensing mechanism 104 dispenses a predetermined amount of sample into a predetermined reaction cell on the reaction disk 109. After that, the reaction disk 109 rotates, and moves the reaction cell into which the sample has been dispensed to an access position of the reagent dispensing mechanism 108.

[0029] The reagent dispensing mechanism 108 dispenses a predetermined amount of reagent into the reaction cell into which the sample has been discharged. Next, the reaction disk 109 rotates, and moves the reaction cell into which the sample and reagent have been discharged to a position where the stirring unit 110 is installed. The sample and reagent are then stirred by the stirring unit 110. The reaction disk 109 is kept at an appropriate temperature to promote the reaction between the sample and the reagent.

[0030] When the reaction process between the sample and reagent on the reaction disk 109 is completed, the reaction disk 109 rotates and moves the reaction cell containing the reaction solution after the reaction to an installation position of the biochemical detection unit 111. Then, the reaction signal is measured by the detection unit in the biochemical detection unit 111. After the signal measurement, the reaction solution is discharged from the reaction cell by the reaction cell washing mechanism 112.

[0031] The above-described mechanism of the automatic analyzer is referred to as the “analysis operation unit.” In addition to the analysis operation unit, the automatic analyzer further includes a control unit 113 and an operation unit 114 that control the overall operation of the automatic analyzer.

[0032] The control unit 113 is composed of, for example, a hardware board and a computer, and is connected to a storage device 115 such as a hard disk. The operation unit 114 is composed of a display unit 117 which is a display equipped with a touch panel, and input devices such as a mouse 118 and a keyboard 119. The storage device 115 stores, for example, analysis items for samples registered by the user. The control unit 113 may be composed of hardware such as a dedicated circuit board, or may be composed of software executed on a computer.

[0033] When configured using hardware, it can be realized by integrating multiple arithmetic units that execute the processing on a wiring board, or in a semiconductor chip or package. When configured using software, it can be realized by installing a high-speed general-purpose CPU in a computer and running a program that executes the desired arithmetic processing. It is also possible to upgrade existing devices using a recording medium on which this program is recorded. Furthermore, these devices, circuits, and computers are connected via wired or wireless networks, and data is sent and received as appropriate.

[0034] The operation of the sample dispensing mechanism in the automatic analyzer according to the present invention will be described below. The reagent dispensing mechanism also has a similar configuration, and the liquid dispensing abnormality detection according to the present invention can be implemented. To avoid redundancy, a description of the reagent dispensing mechanism will be omitted.

[0035] 2 is a schematic diagram of the sample dispensing mechanism. A sample probe 201 is connected to a sample syringe 203 via a flow channel 202, and the insides of these are filled with liquid.

[0036] The specimen syringe 203 is composed of a cylinder 203a and a plunger 203b, and the plunger 203b is connected to a syringe driving means 204. The syringe driving means 204 drives the plunger 203b up and down relative to the cylinder 203a to aspirate and discharge the specimen.

[0037] A motor is connected to the sample probe 201 as a sample probe driving means 205, which moves the sample probe up and down and in a rotational direction to a predetermined position. The syringe driving means 204 and the sample probe driving means 205 are controlled by a sample probe control section 206 (abbreviated as "control section" in Figure 2).

[0038] When aspirating the sample 208 in the container 207, prior to the aspirating operation, a predetermined amount of air (referred to as segmented air) is aspirated into the sample probe 201 to prevent the liquid filled in the sample probe 201 from mixing with the sample 208.

[0039] Thereafter, the specimen probe driving means 205 lowers the specimen probe 201 until it reaches the sample 208, and then performs a suction operation.

[0040] At this time, the specimen probe is lowered by monitoring the amount of change in capacitance caused by the specimen probe 201 reaching the liquid surface of the sample 208, and the specimen probe control unit 206 controls the specimen probe driving means 205 to determine the amount of specimen probe descent.

[0041] After the sample aspirating operation is completed, the sample syringe 203 performs a backlash discharging operation to correct the sample discharging amount in the next discharging operation. Thereafter, the sample probe 201 moves to the sample discharging position, and the sample syringe 203 performs a discharging operation.

[0042] After the discharge, cleaning water 211 in a water supply tank 210 is sprayed out at high pressure by a water supply pump 209, thereby cleaning the sample probe 201. The flow path to the water supply tank is opened and closed by an electromagnetic valve 212. The electromagnetic valve 212 is controlled by the sample probe control unit 206.

[0043] Pressure sensor 213 for measuring the pressure inside flow path 202 is connected to a flow path system including sample probe 201, flow path 202, and sample syringe 203 via branch block 214. Here, pressure sensor 213 is desirably installed as close to sample probe 201 as possible in order to measure pressure fluctuations in sample probe 201 with good sensitivity.

[0044] The output value of the pressure sensor 213 is amplified by a signal amplifier 215 and converted into a digital signal by an A / D converter 216. The digitally converted signal is sent to a calculation unit 218, which calculates a judgment index for judging whether the aspirating was successful (determining whether empty aspirating occurred) using the method described below. A judgment unit 219 compares the judgment index calculated by the calculation unit 218 with a threshold value to determine whether the sample was aspirated successfully.

[0045] In the above dispensing operation, the operation timing of each mechanism is defined within a predetermined time cycle, and continuous dispensing is performed by repeating this cycle.

[0046] FIG. 3 shows the specimen dispensing mechanism aspirating a sample 302 in a sample container 301 (a) normally, (b) performing empty aspirating, and (c) aspirating liquid and air.

[0047] As described above, in the automatic analyzer, the sample dispensing probe 304 detects the sample liquid level from the amount of change in capacitance, and the sample dispensing probe 304 stops below the sample liquid level.

[0048] After aspirating a sample with the tip of the sample dispensing probe holding air 303, backlash discharge is performed. If the liquid level is incorrectly recognized due to air bubbles 305 or the like when the sample dispensing probe 304 is lowered, only air may be aspirated (empty aspirate), or both liquid and air may be aspirated. In this case, the amount of sample discharged will be less than expected, which will affect the analysis results.

[0049] Figure 4 shows the pressure waveforms obtained in a sample dispensing unit equipped with a pressure sensor (a) during sample aspiration and (b) during backlash discharge. The horizontal axis represents time, and the vertical axis represents the pressure value in the dispensing channel output by the pressure sensor. The pressure waveform changes depending on the operation of the sample syringe. The liquid to be aspirated here is assumed to be a sample, detergent, wash water, etc., but is not particularly limited. In the case of a reagent dispensing mechanism, it is assumed to be a reagent, detergent, wash water, etc., but is not particularly limited.

[0050] L1 shows the pressure waveform when a sample is normally aspirated, L2 shows the pressure waveform when dry aspirated, and L3 shows the pressure waveform when liquid and air are aspirated.

[0051] As is clear from this figure, the pressure during aspiration is less likely to show a large difference in waveform between normal (L1) and abnormal (L2, L3) conditions compared to the pressure during backlash discharge. Furthermore, when the dispensing amount differs, the driving amount of the sample syringe 203 differs, and therefore the aspiration time depends on the dispensing amount.

[0052] When analyzing a pressure waveform, if a pressure waveform in a section that depends on the dispensing amount is used, it is necessary to create a judgment parameter according to the dispensing amount, which is expected to complicate the calculation process.

[0053] On the other hand, the pressure waveform during backlash dispensing not only shows a significant difference compared to the pressure waveform during aspiration, but also occurs at the same timing and with the same amount of movement regardless of the dispensing volume. Therefore, it is easier to create judgment parameters to use in pressure analysis during backlash dispensing than in pressure waveform analysis during aspiration.

[0054] Figure 5 shows a method for analyzing the attenuation rate using the waveform during backlash discharge ((a) Acquisition of maximum value, minimum value, and period information (b) Acquisition of baseline and amplitude information). The maximum value in a certain section (time width α) around the time of backlash discharge operation is the initial maximum value P max0 The minimum value is the initial minimum value P min0 The maximum value P max0 and the minimum value P min0 The time taken is t max0 and t min0 Let tmax0 and t min0 The time difference between the two periods is T, and t min0 The maximum value in the range of β with the time after the period T as the median is the first maximum value P max1 The time at this time is t max1 Let's say.

[0055] Next, t max1 The minimum value in the range of γ with the time after the period T as the median is the first minimum value P min1 The time at this time is t min1 After this, the same procedure may be repeated to obtain more maximum and minimum values. The method for obtaining the maximum and minimum values ​​is not limited to this method. For example, a plurality of time intervals may be defined, and the maximum value for each interval may be set as the maximum value, and the minimum value for each interval as the minimum value.

[0056] Next, find the baseline to calculate the amplitude of the waveform. The vertical axis of the pressure waveform is pressure and the horizontal axis is time, and the coordinates are shown in the form of (pressure, time). The midpoint M0 ((t max0 +t min0 ) / 2, (P max0 +P min0 ) / 2) and the midpoint M1 ((t max1 +t min1 ) / 2, (P max1 +P min1 ) / 2) is calculated. The line connecting these midpoints M0 and M1 is determined as the baseline. The method for determining the baseline is not limited to this method. For example, the baseline may be a line that is horizontal to the time axis and has any pressure value.

[0057] Next, calculate the amplitude. The time t at which the initial maximum value is reached max0 The initial maximum value P max0 The distance between the baseline and the initial amplitude A0 is taken as the time t max1 The first maximum value P max1The distance between the pressure value of the initial maximum value and the pressure value of the initial minimum value is defined as the first amplitude A1. The method for calculating the amplitude is not limited to this method. For example, the difference between the pressure value of the initial maximum value and the pressure value of the initial minimum value may be defined as the initial amplitude, and the difference between the pressure value of the first maximum value and the pressure value of the first minimum value may be defined as the first amplitude. Furthermore, the second amplitude A2 and subsequent amplitudes may be calculated.

[0058] Next, the attenuation rate is calculated. The ratio of the initial amplitude A0 to the first amplitude A1 is calculated to calculate the attenuation rate D = A1 / A0. Here, the second amplitude A2 and onward may be used to calculate the attenuation rate. Two or more attenuation rates may also be calculated.

[0059] A function may be provided to determine that the device has malfunctioned if an abnormality is found in the calculation process of the attenuation rate. For example, if there is no pressure fluctuation due to a malfunction of the syringe or pressure sensor, resulting in A0 = A1 = 0 and making it impossible to calculate the attenuation rate, the function may be implemented to halt the attenuation rate calculation and notify the user of the device malfunction.

[0060] FIG. 6 is a graph comparing the attenuation rate during normal aspiration and during empty aspiration. Under each dispensing volume condition, the attenuation rate during normal aspiration and during liquid aspiration can be polarized. The attenuation rate calculated by the calculation unit 218 and the threshold value T h , T i The decay rate is compared with the threshold T h If it is smaller than T, it is normal. h Above and T i If it is below 0, the attenuation rate is T i If it is greater than this, it is determined that the device is faulty.

[0061] Here, the dry suction judgment may be performed using two or more attenuation rates. Also, instead of the judgment using only the attenuation rate, the judgment may be performed by combining the period T as a judgment parameter. h may be variable depending on the amount dispensed and the liquid properties of the sample.

[0062] 7 shows the process flow for detecting a dispensing error during sample dispensing. The specimen dispensing mechanism performs a backlash operation following a sample aspirating operation (S701). The determination unit 219 calculates the attenuation rate from the pressure value in the flow path during this backlash dispensing operation (S702). The determination unit 219 then determines whether the aspiration is normal based on the magnitude relationship between the threshold stored in the determination unit 219 and the attenuation rate (S703).

[0063] If the attenuation rate falls within the normal range, the sample dispensing is determined to be a normal aspiration (S704). If the attenuation rate does not fall within the normal determination range, a determination is made as to whether the aspiration is an empty aspiration based on the magnitude relationship between the threshold value stored in the determination unit 219 and the attenuation rate (S705).

[0064] If the attenuation rate falls within the empty aspiration determination range, the sample dispensing is determined to be empty (S706).If the attenuation rate does not fall within the empty aspiration determination range, it is determined that a hardware abnormality occurred during the sample dispensing process (S707).

[0065] In determining an abnormality, a threshold value for completely empty suction and a threshold value for determining when both air and sample are suctioned may be set to classify the degree of abnormal suction. Furthermore, the determination unit 219 may estimate the cause based on the estimated degree of abnormality.

[0066] For example, if it is determined that the aspiration is completely empty, it is presumed that the cause is not bubbles on the surface of the sample but an abnormality in the dispensing system such as a failure of the syringe. Furthermore, the determination unit 219 may perform a determination not only based on the attenuation rate but also by combining the value calculated by the calculation unit 218, for example, the period T, as a determination parameter.

[0067] As described in Example 1, the present invention can provide an automatic analyzer and an automatic analysis method that can easily and accurately detect abnormalities in liquid dispensing. It can also provide an automatic analyzer and an automatic analysis method that can estimate the cause of an abnormality based on the degree of the abnormality in the abnormality determination.

[0068] Figure 8 shows the relationship between the attenuation rate and the ratio of the actual suction volume to the set suction volume when a certain set suction volume is being sucked. The attenuation rate when air and liquid are sucked deviates from the attenuation rate when the liquid is successfully sucked at the set value, and the degree of this deviation increases with the amount of air sucked.

[0069] By determining the relationship between the ratio of the actual suction volume to the set suction volume and the attenuation rate at multiple points, an approximate curve for estimating the actual suction volume can be determined. By storing this approximate curve for estimating the actual suction volume in the suction volume calculation unit 220 in advance, it becomes possible to calculate the amount of liquid suctioned during the suction operation when determining whether or not dry suction is occurring.

[0070] 101: automatic analyzer, 102: specimen disk, 103: specimen container, 104: specimen dispensing mechanism, 105: reagent storage, 106: reagent disk, 107: reagent container holder, 108: reagent dispensing mechanism, 109: reaction disk, 110: stirring unit, 111: biochemical detection unit, 112: reaction cell cleaning mechanism, 113: control unit, 114: operation unit, 115: storage device, 116: control device, 117: display unit, 118: mouse, 119: keyboard, 120: barcode reader, 201: specimen probe, 202: flow path, 203: specimen syringe, 203a: Cylinder, 203b: plunger, 204: syringe drive means, 205: specimen probe drive means, 206: specimen probe control unit, 207: container, 208: sample, 209: water supply pump, 210: water supply tank, 211: cleaning water, 212: solenoid valve, 213: pressure sensor, 214: branching block, 215: signal amplifier, 216: A / D converter, 217: specimen probe control unit, 218: calculation unit, 219: judgment unit, 220: suction volume calculation unit, 301: sample container, 302: sample, 303: segmented air, 304: sample dispensing probe, 305: air bubbles.

Claims

1. a probe that performs a dispensing operation including a suction and / or a discharge step on a liquid; a syringe that generates pressure fluctuations for dispensing liquid with the probe; a flow channel connecting the probe and the syringe; a sensor for measuring the pressure in the flow channel when dispensing a liquid; a calculation unit that calculates an attenuation rate of a waveform of a pressure change over time measured by the sensor after backlash discharge to eliminate mechanical play of the syringe; a determination unit that determines whether or not an abnormality has occurred in the liquid dispensing process based on the attenuation rate calculated by the calculation unit; An automatic analyzer comprising:

2. (delete)

3. 2. The automatic analyzer according to claim 1, wherein the calculation unit calculates a baseline of the pressure waveform from the maximum and minimum values ​​in a predetermined section of the time-varying waveform of the pressure, and calculates the attenuation rate based on a change in the ratio of the difference between the baseline and the maximum value or the difference between the baseline and the minimum value.

4. 2. The automatic analyzer according to claim 1, wherein the calculation unit further calculates an oscillation period of the waveform of the pressure change over time, and the determination unit uses the oscillation period for the determination.

5. 5. The automatic analyzer according to claim 1, wherein the determining unit makes the determination by comparing the damping rate and / or the oscillation period with a predetermined threshold value.

6. 6. The automatic analyzer according to claim 5, wherein the threshold value is determined based on the damping rate and / or the vibration period when air is also sucked when the liquid is sucked.

7. 7. The automatic analyzer according to claim 6, wherein the threshold value includes a plurality of threshold values ​​according to the amount of the liquid dispensed.

8. 7. The automatic analyzer according to claim 6, wherein the threshold value includes a plurality of threshold values ​​according to the properties of the liquid aspirated by the probe.

9. a probe that performs a dispensing operation including a suction and / or a discharge step on a liquid; a syringe that generates pressure fluctuations for dispensing liquid with the probe; a flow channel connecting the probe and the syringe; a sensor for measuring the pressure in the flow channel when dispensing a liquid; An abnormality determination method for an automatic analyzer comprising: a waveform acquisition step of acquiring a waveform of a change in pressure over time by the sensor after backlash discharge to eliminate mechanical play of the syringe; a decay rate calculation step of calculating a decay rate of pressure based on the time-varying waveform of pressure acquired in the waveform acquisition step; an abnormality determination step of determining whether or not an abnormality has occurred in the liquid dispensing process based on the attenuation rate calculated in the attenuation rate calculation step; A method for determining an abnormality in an automatic analyzer, comprising at least the steps of:

10. 10. The method for determining an abnormality in an automatic analyzer according to claim 9, wherein the attenuation rate calculation step calculates a baseline of the pressure waveform from the maximum and minimum values ​​in a predetermined section of the time-varying waveform of the pressure, and calculates the attenuation rate based on the change in the ratio of the difference between the baseline and the maximum value or the difference between the baseline and the minimum value.

11. 11. The method for determining an abnormality in an automatic analyzer according to claim 10, wherein the predetermined section is a section including at least the initial maximum value and initial minimum value of the time-varying waveform of the pressure from the backlash discharge, and the time during which the waveform takes on the first maximum value and first minimum value that follow them.

12. 4. The automatic analyzer according to claim 3, wherein the predetermined section is a section including at least the initial maximum value and initial minimum value of the time-varying waveform of the pressure from the backlash discharge, and the subsequent first maximum value and first minimum value.