Automatic analysis device, abnormality determination method, and program

Abstract

The purpose of the present invention is to provide an automatic analysis device with which it is possible to accurately measure electrical conductivity in consideration of the influence of the temperature of a liquid, without installing a dedicated temperature sensor. In order to achieve the above, an automatic analysis device according to the present invention comprises: a flow path through which a liquid flows; a liquid feeding mechanism for supplying the liquid to the flow path; an electrical conductivity measurement unit for measuring the electrical conductivity of the liquid within the flow path; a storage unit for storing a threshold value that defines a normal range of the electrical conductivity of the liquid; and a control unit for determining, on the basis of a measurement value for the electrical conductivity of the liquid and the threshold value, whether an abnormality has occurred. The control unit corrects the measurement value for the electrical conductivity of a dilution liquid on the basis of the measurement value for the electrical conductivity of a stock solution, and determines whether an abnormality has occurred on the basis of the corrected value for the electrical conductivity of the dilution liquid and the threshold value.

Description

Automatic analyzer, abnormality determination method and program

[0001] The present invention relates to an automatic analyzer, an abnormality determination method, and a program.

[0002] Automated analyzers perform quantitative and qualitative analysis of components in samples such as serum and urine using optical, electrical, and chemical analytical techniques. Such automated analyzers may measure the conductivity of liquids used for analysis and cleaning to confirm their quality. However, because the conductivity of liquids varies depending on environmental factors, it is difficult to accurately confirm their quality without taking these variations into account. Therefore, for example, the technology described in Patent Document 1 takes into account the influence of temperature, one of the environmental factors, and converts the measured conductivity (electrical conductivity) to a standard temperature (25°C).

[0003] JP 2012-189552 A

[0004] In the technology described in Patent Document 1, a temperature sensor is provided to correct for the influence of temperature, and the measurement value of the conductivity sensor is converted to a standard temperature based on the liquid temperature measured by the sensor. In other words, with the technology described in Patent Document 1, the installation of the temperature sensor may restrict the installation space for the conductivity sensor and increase costs.

[0005] An object of the present invention is to provide an automatic analyzer that can accurately measure the conductivity of a liquid while taking into account the influence of the temperature of the liquid, without the need for a dedicated temperature sensor.

[0006] In order to solve the above-mentioned problems, the automatic analyzer of the present invention comprises a flow path through which a liquid flows, a liquid delivery mechanism that supplies the liquid to the flow path, a conductivity measuring unit that measures the conductivity of the liquid in the flow path, a memory unit that stores a threshold value that defines a normal range for the conductivity of the liquid, and a control unit that determines whether or not an abnormality exists based on the measured value of the conductivity of the liquid and the threshold value, and the control unit corrects the measured value of the conductivity of the diluted liquid based on the measured value of the conductivity of the undiluted liquid, and determines whether or not an abnormality exists based on the corrected value of the conductivity of the diluted liquid and the threshold value.

[0007] According to the present invention, an automatic analyzer can be provided that is capable of accurately measuring the conductivity of a liquid while taking into account the influence of the temperature of the liquid, without the need for a dedicated temperature sensor.

[0008] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0009] FIG. 1 is a schematic configuration diagram of an automatic analyzer. FIG. 2 is a block diagram showing the functional configuration of a conductivity measuring unit. FIG. 3 is a block diagram showing the functional configuration of an analyzer PC. FIG. 4 is a graph showing the relationship between liquid temperature and conductivity. FIG. 5 is a flowchart showing the operation of a cleaning unit during preparation for analysis and during analysis in an automatic analyzer according to Example 1. FIG. 6 is a flowchart showing the operation of a circuit for acquiring conductivity during analysis. FIG. 7 is a flowchart showing the operation of a failure mode diagnosis. FIG. 8 is a flowchart showing the operation during analysis and when an abnormality is determined in an automatic analyzer according to Example 2.

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0011] The automated analyzer of this embodiment dispenses a sample and a reagent into a reaction cell and automatically analyzes the sample components. However, if a mixture of sample and reagent from a previous analysis remains in the reaction cell, it will affect the next analysis. Therefore, the reaction cell is cleaned with a cleaning solution after each analysis. The cleaning solution used in this process is a diluted detergent solution prepared by diluting a stock detergent. However, if the concentration is too low, cleaning will be insufficient, and if the concentration is too high, residual detergent components will adversely affect the analysis results. Therefore, to perform accurate analysis, cleaning with a diluted detergent solution of an appropriate concentration is required. Therefore, the automated analyzer of this embodiment has the function of measuring the conductivity of the diluted detergent solution dispensed each time the reaction cell is cleaned, determining whether the concentration of the diluted detergent solution is within a normal range, and outputting an alarm if an abnormality is detected. Below, a specific description is given using Examples 1 and 2.

[0012] 1 is a schematic diagram of an automatic analyzer. As shown in FIG. 1, the automatic analyzer of this embodiment includes an analysis unit 11, a cleaning unit 12, a waste liquid section 13, a probe cleaning flow path 14, and an analyzer PC 20.

[0013] The analysis unit 11 is a unit that analyzes samples and includes a dispensing probe 401, a reaction cell 402, and an analysis / measurement unit 403. The dispensing probe 401 dispenses samples, reagents, and pure water into the reaction cell 402. The reaction cell 402 includes multiple small cells, into which samples and reagents are dispensed and from which diluted detergent solution is discharged. Each cell is assigned a cell number. The analysis / measurement unit 403 measures the sample dispensed into the reaction cell 402 and obtains a measurement value. Measurement methods performed by the analysis / measurement unit 403 include absorbance measurement, scattering measurement, electrolytic analysis measurement, immunoassay, and mass spectrometry measurement. The analysis / measurement unit 403 can perform measurements using these measurement methods or a combination of these measurement methods.

[0014] The cleaning unit 12 is a unit that dilutes a detergent stock solution with pure water and discharges the resulting diluted detergent solution into the reaction cell 402 to clean the inside of the reaction cell 402. The cleaning unit 12 includes solenoid valves V1, V2, V3, and V4, a detergent bottle 101, a pure water tank 102, a dilution section 103, a vacuum bottle 104, a vacuum pump VP1, a supply pump P1, a detergent syringe 105, a cleaning liquid discharge mechanism 106, and a conductivity measuring section 30. In the cleaning unit 12, the flow paths through which the liquid flows up to the cleaning liquid discharge mechanism 106 may be collectively referred to as the "supply flow paths." Furthermore, the mechanisms that supply the liquid to the supply flow paths, such as the vacuum pump VP1, the supply pump P1, the detergent syringe 105, and the solenoid valves V1 to V4, may be collectively referred to as the "liquid delivery mechanism."

[0015] Each solenoid valve has the function of opening and closing a supply flow path by passing an electric current through a built-in electromagnet. Solenoid valve V1 controls the supply of detergent from detergent bottle 101, solenoid valve V2 controls the supply of detergent to dilution unit 103, solenoid valve V3 controls the suction of detergent by vacuum bottle 104, and solenoid valve V4 controls the supply of pure water to dilution unit 103. When vacuum pump VP1 generates a vacuum, negative pressure is created inside vacuum bottle 104, resulting in the suction of undiluted detergent from detergent bottle 101 and the delivery of the undiluted detergent into dilution unit 103. The amount of delivery depends on the open time of solenoid valve V2 and the inner diameter and length of the flow path connected to dilution unit 103.

[0016] The supply pump P1 sends pure water from the pure water tank 102 to the dilution section 103. The amount of liquid sent depends on the open time of the solenoid valve V4. After the vacuum bottle 104 sends the undiluted detergent solution to the dilution section 103, the supply pump P1 sends pure water to the dilution section 103. The momentum of the pure water supplied from the supply pump P1 agitates the undiluted detergent solution and the pure water, diluting the detergent. Furthermore, the water momentum of the supply pump P1 not only dilutes the detergent, but also serves to send the diluted detergent solution to the conductivity measuring section 30 and the cleaning liquid discharging mechanism 106. The cleaning liquid discharging mechanism 106 discharges the sent diluted detergent solution into the reaction cell 402.

[0017] The detergent syringe 105 is connected to a supply flow path between the solenoid valves V1 and V2. The detergent syringe 105 is capable of aspirating the undiluted detergent from the detergent bottle 101 and delivering the undiluted detergent to the conductivity measuring unit 30 and the cleaning liquid dispensing mechanism 106 without diluting it in the dilution unit 103. Specifically, first, the solenoid valve V1 opens, the solenoid valve V2 closes, and the detergent syringe 105 performs a suction operation, thereby aspirating a certain amount of undiluted detergent from the detergent bottle 101. Thereafter, the solenoid valves V1 and V3 close, the solenoid valve V2 opens, and the detergent syringe 105 performs a discharge operation, thereby delivering the undiluted detergent to the conductivity measuring unit 30. These two operations are repeated multiple times, until the flow path (measurement flow path) in which the conductivity measuring unit 30 is located is filled with the undiluted detergent. In this state, the conductivity measuring unit 30 measures the conductivity of the undiluted detergent. Thereafter, the diluted detergent solution is sent to the conductivity measuring unit 30 by the water force of the supply pump P1, whereby the undiluted detergent solution is pushed out from the conductivity measuring unit 30 and discharged from the cleaning liquid discharging mechanism 106 into the reaction cell 402. The undiluted detergent solution discharged into the reaction cell 402 is sent to the waste liquid unit 13 and then discharged outside the device. The detergent syringe 105 is also connected to the probe washing flow path 14 described below, and can also send the undiluted detergent solution to the probe washing flow path 14.

[0018] The waste liquid section 13 and the probe washing flow path 14 are connected to the flow paths within the washing unit 12. The waste liquid section 13 discharges the liquid that has been sent and accumulated in the vacuum bottle 104, the liquid after analysis in the reaction cell 402, and the like, to the outside of the device. The probe washing flow path 14 is a flow path for supplying detergent from the detergent bottle 101 when washing the dispensing probe 401. During analysis, a solenoid valve (not shown) is controlled so that detergent is not sent to the probe washing flow path 14.

[0019] Next, the conductivity measurement unit 30 will be described using FIG. 2 . FIG. 2 is a block diagram showing the functional configuration of the conductivity measurement unit. As shown in FIG. 2 , the conductivity measurement unit 30 includes a conductivity sensor 301, a measurement circuit 302, and a discharge circuit 303. The conductivity sensor 301 is composed of a pair of electrodes, each of which is disposed in a supply flow path (measurement flow path) between the dilution unit 103 and the cleaning liquid discharge mechanism 106. The measurement circuit 302 is composed of a power supply, resistors, capacitors, diodes, operational amplifiers, and the like (not shown). It applies a voltage to the conductivity sensor 301 and obtains the conductivity from an output voltage including the electrical resistance of the liquid (undiluted detergent or diluted detergent) between the electrodes in the measurement flow path. The discharge circuit 303 is composed of a transistor, resistors, and the like. When the voltage application by the measurement circuit 302 ends, the transistor performs a logic inversion, discharging the charge from the capacitor in the measurement circuit 302.

[0020] Here, the reason for measuring the conductivity of the diluted solution in this example is to determine the detergent concentration of the diluted solution. It is known that the higher the concentration of a solution, the greater the electrolyte concentration in the solution, which decreases the electrical resistivity of the solution, thereby increasing the conductivity. It is also known that there is a proportional relationship between conductivity and concentration. Therefore, by measuring the conductivity of the diluted solution, the detergent concentration of the diluted solution can be calculated.

[0021] FIG. 3 is a block diagram showing the functional configuration of the analyzer PC. FIG. 3 mainly shows the operational sequence for measuring the conductivity of the liquid in the measurement flow path and the operational sequence for determining whether the measured value of the dilution solution is within a predetermined range. As shown in FIG. 3 , the analyzer PC 20 includes a control unit 21, an operation unit 22, a display unit 23, and a memory unit 24. The control unit 21 is, for example, a CPU, and controls the operation unit 22, the display unit 23, and the memory unit 24. The control unit 21 is also connected to each mechanism, such as the analysis unit 11, the cleaning unit 12, and the conductivity measurement unit 30, via an interface. It controls the operation of each mechanism and performs predetermined calculations using measurements received from the analysis unit 11 and the conductivity measurement unit 30. The display unit 23 is, for example, a liquid crystal display (LCD) that displays analysis information, including analysis results and abnormality determination results, to the user. The operation unit 22 is, for example, a keyboard or mouse that accepts user operations, such as pressing buttons on various operation screens displayed on the display unit 23 with the mouse cursor, clicking the mouse, or entering numbers and characters into input boxes from the keyboard. The storage unit 24 is composed of a memory 50 and a storage 60 .

[0022] The memory 50 stores programs corresponding to the functions executed by the control unit 21, conceptually as a mechanism control unit 501, a correction unit 502, and an abnormality determination unit 503. The mechanism control unit 501 controls the operation of each mechanism. The correction unit 502 corrects the measured value of the conductivity of the diluted solution measured by the conductivity measurement unit 30 based on the measured value of the conductivity of the undiluted solution measured by the conductivity measurement unit 30, and will be described in detail later. The abnormality determination unit 503 determines whether or not an abnormality exists based on the corrected value of the conductivity of the diluted solution and a preset threshold value, and will be described in detail later.

[0023] Here, the program may be provided by being pre-installed in a ROM or the like, or may be provided or distributed by being recorded in an installable or executable file on a computer-readable recording medium such as a CD-ROM. Furthermore, the program may be stored on a computer connected to a network such as the Internet and provided or distributed by being downloaded via the network.

[0024] The storage 60 stores threshold information 601, correction conditions 602, correction results 603, etc. The threshold information 601 stores a threshold that defines a normal range for the conductivity of the diluent. Note that the normal range varies depending on the temperature, so for example, a threshold that defines a normal range at a reference temperature is stored. The correction conditions 602 store various information used to correct the conductivity of the diluent, such as the reference temperature, the conductivity of the undiluted solution at the reference temperature, and correspondence information that defines the relationship between the conductivity of the undiluted solution or the diluent and the temperature. The correction results 603 store a correction value for the conductivity of the diluent, etc.

[0025] In this embodiment, the processing by the control unit 21 of the analyzer PC 20, which is a computer included in the automatic analyzer, will be described below, but if another computer is communicatively connected to the analyzer PC 20 via a network or the like, the other computer may execute the same processing. In this case, programs such as the correction unit 502 and the abnormality determination unit 503 described above will be installed in the other computer.

[0026] Next, a method will be described in which the control unit 21 of the analytical device PC 20 determines whether or not the concentration of the diluent is abnormal based on the measured value of the conductivity of the diluent measured by the conductivity measurement unit 30 and the threshold value stored in the storage 60. The conductivity measurement unit 30 transmits the measured value of the conductivity of the liquid in the measurement flow path to the analytical device PC 20. However, the conductivity of the liquid varies depending on the temperature of the liquid, even if the detergent concentration of the liquid is the same. For this reason, the correction unit 502 in this embodiment identifies the temperature of the liquid in the measurement flow path and converts the measured conductivity value to the conductivity at a reference temperature.

[0027] First, a method for determining the temperature of the liquid in the measurement flow path will be described. Fig. 4 is a graph showing the relationship between the temperature of the liquid and the conductivity. As shown in Fig. 4, in the temperature environment in which the automatic analyzer is used, the conductivity and the temperature are proportional to each other. Here, the temperature at the time of measurement is T, the conductivity at the temperature at the time of measurement is K, and the reference temperature is T. ０ , and the temperature coefficient (corresponding information that determines the relationship between the conductivity of the liquid and the temperature) is a, the conductivity at the reference temperature is K ０ is generally expressed by the following formula (1): ０ = K / (1 + a × (T ０ −T)) (Equation 1) In this embodiment, in (Equation 1), the reference temperature (T ０ ), temperature coefficient (a), conductivity of the original solution at the reference temperature (K' ０ ), are stored in advance in the storage 60 as correction conditions 602. Therefore, the correction unit 502 of this embodiment calculates the temperature at the time of measurement (T) by substituting these values ​​and the value of the conductivity (K') of the undiluted solution measured by the conductivity measuring unit 30 into (Equation 1). In this embodiment, the reference temperature (T ０ ) is set to 25°C, but it may be set to a value other than 25°C. Furthermore, the temperature coefficient (a) will be different depending on the type of stock solution, but will be the same for the stock solution and the diluted solution obtained by diluting the stock solution. As described above, this embodiment has the advantage that the temperature of the liquid in the measurement flow path can be determined without installing a dedicated temperature sensor for correction, thereby reducing the cost and space required to install a temperature sensor.

[0028] Next, a method for converting the measured conductivity into the conductivity at a reference temperature will be described. The conductivity measuring unit 30 measures the conductivity of the stock solution, then dilutes the stock solution, and measures the conductivity of the resulting diluted solution. Here, since the detergent bottle 101 and the pure water tank 102 are in the same automatic analyzer, the temperature of the pure water used to dilute the stock solution is the same as that of the stock solution, and the diluted solution and the stock solution are at the same temperature. Then, the correction unit 502 of this embodiment calculates the conductivity (K'') of the diluted solution measured by the conductivity measuring unit 30, the temperature coefficient (a), and the reference temperature (T ０= 25) and the temperature at the time of measurement (T) calculated as described above are substituted into (Equation 1). As a result, the measured value of the conductivity of the diluted solution (K'') is converted into the conductivity at the reference temperature to obtain a corrected value (K'' ０ ) is calculated, and the calculation result is stored in the storage 60 as a correction result 603.

[0029] Next, a method for the abnormality determination unit 503 to determine whether or not there is an abnormality in the detergent concentration of the diluent based on the conductivity of the diluent at the reference temperature and the threshold value will be described. The abnormality determination unit 503 first reads the threshold value defining the normal range at the reference temperature, which is stored in the storage 60 as threshold value information 601. Next, the abnormality determination unit 503 compares the corrected value of the conductivity of the diluent calculated as described above with the read threshold value. If the corrected value of the conductivity of the diluent is outside the normal range defined by the threshold value, the abnormality determination unit 503 determines that the concentration is abnormal and outputs an alarm on the display unit 23. At this time, the mechanism control unit 501 stops the operation of the dispensing probe 401 in the analysis unit 11, the liquid delivery mechanism and cleaning liquid discharge mechanism 106 in the cleaning unit 12, etc.

[0030] 5 is a flowchart showing the operation of the cleaning unit during preparation for analysis and during analysis in the automatic analyzer according to Example 1. The analysis preparation operation and analysis operation of the cleaning unit 12 in this example will be described below with reference to FIG.

[0031] In the analysis preparation operation, first, in step S1, the mechanism control unit 501 performs an initialization operation for all mechanisms in the cleaning unit 12. This operation is intended to return the mechanisms to the initial operating state before the start of the analysis if the mechanisms have stopped midway through a previous analysis due to factors such as an abnormal stoppage of the automatic analyzer.

[0032] In step S2, the mechanism control unit 501 operates the detergent syringe 105 multiple times to send the undiluted detergent solution to the conductivity measuring unit 30, and fills the measurement flow path with the undiluted detergent solution.

[0033] Thereafter, in step S3, the conductivity measuring unit 30 acquires the conductivity of the undiluted detergent solution.

[0034] Then, in step S4, the correction unit 502 determines the temperature of the undiluted detergent based on the values ​​stored as the correction conditions 602 in the storage 60 and the conductivity of the undiluted detergent obtained in step S3, as described above. The determined temperature is stored in the storage 60 as, for example, the correction conditions 602.

[0035] The above-described steps S1 to S4 are performed as an analysis preparation operation in the washing unit 12. After the analysis preparation operation is completed, when the user operates, for example, the start button on the operation unit 22, the analysis operation starts.

[0036] In the analysis operation, first, in step S5, the mechanism control unit 501 operates the supply pump P1 and the vacuum pump VP1 to send the diluted detergent solution from the dilution unit 103 to the cleaning solution discharge mechanism 106. The sent diluted detergent solution is discharged from the cleaning solution discharge mechanism 106 into the reaction cell 402 and is used to wash the reaction cell 402.

[0037] Next, in step S6, the conductivity measuring unit 30 acquires the conductivity of the diluted detergent solution. This conductivity acquisition is performed while the diluted detergent solution is being sent from the dilution unit 103 to the cleaning solution dispensing mechanism 106. A specific method for acquiring the conductivity will be described later.

[0038] Next, in step S7, the correction unit 502 corrects the conductivity of the diluted detergent solution based on the conductivity of the diluted detergent solution acquired in step S6 and the temperature specified in step S4.

[0039] In step S8, the abnormality determination unit 503 compares the corrected value of the conductivity of the diluted detergent solution obtained in step S7 with the threshold value read from the threshold information 601 in storage 60 to determine whether the conductivity of the diluted detergent solution is within the normal range.

[0040] If the conductivity of the diluted detergent solution is within the normal range, the process proceeds to step S9, where the corrected value (within the normal range) of the conductivity of the diluted detergent solution is stored in the storage 60 as the correction result 603. Then, in step S10, the mechanism control unit 501 compares the current number of washes with the number of washes (number of samples) required for the current analysis to determine whether to terminate the cleaning operation. If it is determined that the required number of washes has not been reached, the process proceeds again to step S5, where the mechanism control unit 501 performs a cleaning operation on the uncleaned cells among the multiple cells included in the reaction cell 402, while acquiring the conductivity of the diluted detergent solution and determining whether an abnormality has occurred, as in steps S6 to S9. Furthermore, if it is determined in step S10 that the required number of washes has been reached, the process terminates the cleaning operation and proceeds to step S11. In step S11, the temperature identified in step S4 is deleted from, for example, the correction condition 602 in the storage 60. Then, the operation of the cleaning unit 12 ends, and the analysis by the automated analyzer is completed.

[0041] On the other hand, if the conductivity of the diluted detergent solution is outside the normal range in step S8, the process proceeds to step S12, where the mechanism control unit 501 stops the operation of the vacuum pump VP1 and the supply pump P1 and closes the solenoid valves V1 to V4, thereby suspending the cleaning operation by the cleaning unit 12. At this time, the analysis operation itself is not suspended, and additional analysis becomes unavailable, causing the display unit 23 to output information indicating that additional analysis cannot be performed. Then, in step S13, the corrected value (outside the normal range) of the conductivity of the diluted detergent solution is stored in the storage 60 as the correction result 603. Furthermore, in step S14, an alarm is output to the display unit 23, indicating that an abnormality has occurred in the concentration of the diluted detergent solution diluted in the dilution unit 103.

[0042] Note that the analysis that was in progress when the cleaning operation was interrupted in step S12 continues to be executed, and when the analysis is completed, the analysis results are output to the display unit 23, even after an alarm has been output. The automated analyzer then completes the analysis operation, releases the interruption of the cleaning operation by the cleaning unit 12, and deletes the information indicating that additional analysis cannot be performed from the display unit 23. However, the concentration abnormality alarm continues to be output to the display unit 23 even after the automated analyzer has completed its analysis operation.

[0043] In this embodiment, the conductivity of the diluted detergent solution is measured each time the solution is supplied to the measurement flow path by the solution delivery mechanism, making it possible to clearly determine when an abnormality in concentration occurred, thereby preventing additional analysis using a cell cleaned with the diluted detergent solution of an abnormal concentration.

[0044] As shown in FIG. 5 , the cleaning operation of the reaction cell 402 in the cleaning unit 12 is performed multiple times depending on the required number of cleanings (number of samples), significantly affecting the processing speed of the automated analyzer. To improve analytical throughput, one cycle of the cleaning operation in the cleaning unit 12 (steps S5 to S9 in FIG. 5 ) must be completed in a relatively short time, for example, within four seconds. However, if one cycle of the cleaning operation is performed consecutively, the measurement interval between cycles in the conductivity measurement unit 30 also becomes short. As a result, the charge accumulated in the capacitor when the measurement circuit 302 of the conductivity measurement unit 30 applied a voltage to the conductivity sensor 301 in the previous cycle may remain in the subsequent cycle, making it difficult to accurately measure the conductivity. Therefore, in this embodiment, as shown in FIG. 2 , a discharge circuit 303 is provided in the conductivity measurement unit 30. This discharge circuit 303 enables the discharge of charge from the capacitor in the measurement circuit 302 even when the measurement interval between cycles is short. In other words, since the conductivity can be measured continuously without any residual charge remaining in the capacitor, it is possible to increase the analytical throughput while maintaining the accuracy of the conductivity measurement.

[0045] The method of measuring the conductivity by the conductivity measuring unit 30 in one cycle of the cleaning operation, i.e., the process in step S6 described above, will now be described in detail with reference to Fig. 6. Fig. 6 is a flowchart showing the circuit operation for acquiring the conductivity during analysis.

[0046] First, in step S 6 - 1 , the power supply of the measurement circuit 302 applies a voltage to the measurement circuit 302 and the conductivity sensor 301 .

[0047] Thereafter, in step S6-2, the measurement circuit 302 obtains the conductivity based on the amount of voltage drop.

[0048] Furthermore, in step S 6 - 3 , the power supply for the measurement circuit 302 stops applying voltage to the measurement circuit 302 and the conductivity sensor 301 .

[0049] Thereafter, in step S6-4, the transistor of the discharge circuit 303 inverts the logic of the discharge circuit 303, triggered by the end of the voltage application in step S6-3.

[0050] Then, in step S6-5, the discharge circuit 303 discharges the charge from the capacitor in the measurement circuit 302. When the discharge of the charge is completed, the process returns to step S6-1 to move on to the next cycle of the cleaning operation. At this time, the application of voltage triggers the logic of the discharge circuit 303 to be inverted, thereby preventing the discharge circuit 303 from discharging the charge in the capacitor while the voltage is being applied.

[0051] Next, we will explain the failure mode diagnosis, which diagnoses the cause (type) of an abnormality in the concentration of the diluted detergent solution. As mentioned above, if an abnormality occurs in the concentration of the diluted detergent solution, the display unit 23 outputs an alarm in step S14 of FIG. 5. However, this alarm alone does not reveal the cause of the abnormal concentration, so the user must investigate the cause themselves. Therefore, it is effective for the automatic analyzer to automatically execute a failure mode after step S14 of FIG. 5. In the failure mode, the abnormality determination unit 503 identifies which of the solenoid valves V1 to V4 and the conductivity sensor 301 may be malfunctioning (abnormal), and outputs the identification result as an alarm. The operation of the failure mode diagnosis will be explained below using FIG. 7.

[0052] 7 is a flowchart showing the operation of the failure mode diagnosis, which is executed following step S14 if the conductivity of the diluted detergent solution is outside the normal range in step S8 of FIG.

[0053] First, in step S15, the abnormality determination unit 503 checks the trend of the corrected value of the conductivity of the diluted detergent solution stored in the storage 60, and determines whether the conductivity is on an increasing trend. One possible method for checking the trend is to use a method in which the horizontal axis represents the number of measurements or measurement time of the conductivity, and the vertical axis represents the conductivity, and check whether the slope is positive or negative.

[0054] If it is determined in step S15 that the conductivity is on the rise, then in step S16, the abnormality determination unit 503 determines whether the corrected value (outside the normal range) of the conductivity of the diluted detergent stored in the storage 60 in step S13 is within a first abnormal range that is higher than the normal range. The first abnormal range is a range close to the undiluted detergent that is determined by a different threshold value that is higher than the threshold value that defines the normal range, and is stored in advance in the storage 60 as threshold value information 601.

[0055] If it is determined in step S16 that the corrected value of the conductivity of the diluted detergent is within the first abnormal range, the process proceeds to step S17, where the abnormality determination unit 503 determines that there is an abnormality in the conductivity sensor 301, and outputs an alarm to that effect to the display unit 23. This is because even if an opening / closing abnormality occurs in any of the solenoid valves V1 to V4, diluted detergent with a concentration so high that it falls within the first abnormal range will not flow into the conductivity measurement unit 30.

[0056] On the other hand, if it is determined in step S16 that the corrected value of the conductivity of the diluted detergent solution is not within the first abnormal range, the process proceeds to step S18, where the abnormality determination unit 503 determines that the solenoid valve V3 is abnormally closed, and outputs an alarm to that effect on the display unit 23. The abnormality of being closed includes a state in which the solenoid valve does not close and remains open, and a state in which the solenoid valve does not close completely and there is a gap.

[0057] If it is determined in step S15 that the conductivity is not increasing, i.e., is decreasing, then in step S19, the abnormality determination unit 503 determines whether the corrected value (outside the normal range) of the conductivity of the diluted detergent solution stored in the storage 60 in step S13 is within a second abnormal range that is lower than the normal range. The second abnormal range is a range close to that of pure water, determined by another threshold value lower than the threshold value that defines the normal range, and is pre-stored in the storage 60 as threshold value information 601.

[0058] If it is determined in step S19 that the corrected value of the conductivity of the diluted detergent solution is within the second abnormal range, the process proceeds to step S20, where the abnormality determination unit 503 determines that the solenoid valves V1 to V3 are abnormally open, and outputs an alarm to that effect to the display unit 23. An open abnormality is a state in which the solenoid valves remain closed without opening.

[0059] On the other hand, if it is determined in step S19 that the corrected value of the conductivity of the diluted detergent solution is not within the second abnormal range, the process proceeds to step S21, where the abnormality determination unit 503 determines whether the decreasing trend of the conductivity is a sudden decreasing trend. Note that, as a method for determining whether or not the decreasing trend is a sudden decreasing trend, a method of determining whether or not the absolute value of the aforementioned slope is greater than a slope threshold value stored in advance in the storage 60 can be considered.

[0060] If it is determined in step S21 that there is a rapid decrease in the pressure, the process proceeds to step S22, where the abnormality determination unit 503 determines that there is an abnormality in the closed state of the solenoid valve V4, and outputs an alarm to the display unit 23 to notify this fact.

[0061] On the other hand, if it is determined in step S21 that there is no sudden decrease in the pressure, the process proceeds to step S23, where the abnormality determination unit 503 determines that the solenoid valve V2 is abnormally closed, and outputs an alarm to the display unit 23 to notify the user of this.

[0062] As mentioned above, causes of abnormalities in the concentration of diluted detergent include malfunctioning of the solenoid valve. Causes of solenoid valve malfunction include internal factors such as deterioration or failure of the coil or packing that make up the solenoid valve, and external factors such as foreign matter entering the opening and closing part of the solenoid valve. If the solenoid valve malfunctions due to external factors, the malfunction may be resolved by continuing to dispense diluted detergent.

[0063] In Example 1, if the conductivity of the diluted detergent solution is outside the normal range in step S8 of FIG. 5 , the cleaning operation by the cleaning unit 12 is interrupted in step S12, and additional analysis is not possible. However, in Example 2, if the conductivity of the diluted detergent solution is outside the normal range in step S8, the use of the cell that was cleaned with that diluted detergent solution is stopped, but analysis of the other cells is continued. Furthermore, in Example 2, the cleaning operation by the cleaning unit 12 is interrupted only if the conductivity of the diluted detergent solution subsequently dispensed is determined to be abnormal multiple times in succession. This has the advantage of allowing analysis to be continued if a concentration abnormality occurring during analysis by the automated analyzer is a temporary solenoid valve abnormality caused by an external factor.

[0064] Specific operations in the second embodiment will be described below with reference to Fig. 8. Fig. 8 is a flowchart showing operations during analysis and when an abnormality is determined in the automatic analyzer according to the second embodiment.

[0065] The analysis preparation operation is the same as steps S1 to S4 in FIG. 5 corresponding to the first embodiment.

[0066] After the start of the analysis operation, steps S5 to S7 are the same as those in the first embodiment.

[0067] However, if the conductivity of the diluted detergent solution is determined to be outside the normal range in step S8, in Example 2, the process proceeds to step S24, where the mechanism control unit 501 identifies the cell number of the cell that was washed with the diluted detergent solution determined to be abnormal and disables analysis using that cell. At this time, cells other than the identified cell number remain available for additional analysis. When additional analysis is performed, the mechanism control unit 501 skips the cell for which analysis is disabled and performs analysis on the cell with the next cell number.

[0068] Next, in step S25, the corrected value (outside the normal range) of the conductivity of the diluted detergent is stored in the storage 60 as the correction result 603.

[0069] Thereafter, in step S26, the abnormality determination unit 503 determines whether the abnormality determination that the conductivity is outside the normal range has occurred a predetermined number of times or more in succession. The predetermined number of times that serves as the basis for this determination is stored in advance in the storage 60, and is set to six in this embodiment, but is not limited to this number. If the number of consecutive abnormality determinations is less than the predetermined number, the process proceeds to step S5, where the next cell is cleaned.

[0070] On the other hand, if the number of consecutive abnormality determinations is equal to or exceeds the predetermined number in step S26, it is considered highly likely that the solenoid valve abnormality is not a transient one. Therefore, the process proceeds to step S27, and the cleaning operation by the cleaning unit 12 is interrupted, as in step S12 in FIG. 5 corresponding to the first embodiment, and further analysis cannot be performed.

[0071] Thereafter, in step S28, an alarm indicating that an abnormality has occurred in the concentration of the diluted detergent solution is output to the display unit 23. Thereafter, the failure diagnosis mode shown in Fig. 7 is executed as necessary.

[0072] Furthermore, even if the conductivity of the diluted detergent solution is within the normal range in step S8, steps S9 to S11 are the same as in the first embodiment.

[0073] However, in the second embodiment, after step S11, in step S30, the abnormality determination unit 503 determines whether or not there is a cell that has become unusable (unavailable for analysis execution) in step S24. If there is no cell that has become unusable, the analysis operation ends.

[0074] On the other hand, if there are any unusable cells in step S30, the process proceeds to step S31, where all of the unusable cells are re-cleaned and made usable for the next analysis and thereafter.

[0075] The present invention is not limited to the above-described embodiments, and various modifications are possible.

[0076] For example, in the above-described embodiment, the temperatures of the stock solution and the diluent are identified and the measured conductivity values ​​are corrected based on those temperatures. However, the measured conductivity values ​​may be corrected directly without identifying the temperature of the stock solution, etc. A specific example will be given below. First, a correction formula for correcting the measured conductivity values ​​of the diluent for each conductivity of the stock solution is stored in advance in the storage 60 as a correction condition 602. Then, the correction unit 502 identifies the corresponding correction formula from the storage 60 based on the measured conductivity values ​​of the stock solution acquired by the conductivity measurement unit 30. Next, the correction unit 502 corrects the measured conductivity values ​​of the diluent based on the identified correction formula and the measured conductivity values ​​of the diluent acquired by the conductivity measurement unit 30.

[0077] Furthermore, for example, in the above-described embodiment, the measured value of the conductivity of the dilute solution is corrected and compared with the threshold value. However, the threshold value may be corrected and compared with the measured value of the conductivity of the dilute solution. An example will be specifically described below. First, a threshold value at a reference temperature is stored in advance in the storage 60 as threshold information 601, and correspondence information defining the relationship between the conductivity of the stock solution and the threshold value is stored in advance in the storage 60 as correction condition 602. Then, the correction unit 502 corrects the threshold value at the reference temperature based on the measured value of the conductivity of the stock solution acquired by the conductivity measuring unit 30 and the correspondence information. The corrected value of the threshold value is stored in the storage 60 as a correction result 603. Thereafter, the abnormality determination unit 503 determines whether or not an abnormality exists based on the measured value of the conductivity of the dilute solution and the corrected value of the threshold value.

[0078] Furthermore, for example, in the above-described embodiment, the reference temperature, the conductivity of the stock solution at the reference temperature, and the temperature coefficient were used to identify the temperature of the stock solution, but other information may also be used. A specific example will be described below. First, as the correction condition 602, correspondence information defining the relationship between the temperature in 1°C increments within a certain range and the conductivity of the stock solution is stored in advance in the storage 60. Then, the correction unit 502 identifies the temperature of the stock solution based on the measured value of the conductivity of the stock solution acquired by the conductivity measurement unit 30 and the correspondence information.

[0079] Furthermore, for example, in the above-described embodiment, the concentration abnormality of a diluted detergent solution obtained by diluting a stock solution of a detergent with pure water was determined, but it is also possible to determine the concentration abnormality of a diluted solution obtained by diluting a stock solution of a reagent other than a detergent with pure water.

[0080] 11...analysis unit, 12...cleaning unit, 13...waste liquid section, 14...probe cleaning flow path, 20...analysis device PC, 21...controller, 22...operation section, 23...display section, 24...storage section, 30...conductivity measurement section, 50...memory, 60...storage, 101...detergent bottle, 102...pure water tank, 103...dilution section, 104...vacuum bottle, 105...detergent syringe, 106...cleaning liquid discharge mechanism, 301...conductivity sensor, 302...measurement circuit, 303...discharge circuit, 401...dispensing probe, 402...reaction cell, 403...analysis measurement section, 501...mechanism control section, 502...correction section, 503...abnormality determination section, 601...threshold value information, 602...correction conditions, 603...correction results, V1 to V4...solenoid valves, VP1...vacuum pump, P1...supply pump

Claims

1. An automatic analyzer comprising: a flow path through which a liquid flows; a liquid delivery mechanism that supplies the liquid to the flow path; a conductivity measurement unit that measures the conductivity of the liquid in the flow path; a memory unit that stores a threshold value that defines a normal range for the conductivity of the liquid; and a control unit that determines whether or not there is an abnormality based on the measured value of the conductivity of the liquid and the threshold value, wherein the control unit corrects the measured value of the conductivity of the diluted liquid based on the measured value of the conductivity of the undiluted liquid, and determines whether or not there is an abnormality based on the corrected value of the conductivity of the diluted liquid and the threshold value.

2. An automatic analyzer according to claim 1, wherein the control unit corrects the threshold value in place of the measured value of the conductivity of the diluted solution, and determines whether or not an abnormality exists based on the measured value of the diluted solution and the corrected value of the threshold value in place of the corrected value of the conductivity of the diluted solution and the threshold value.

3. An automatic analyzer according to claim 1, wherein the control unit determines the temperatures of the original solution and the diluted solution based on the measured value of the conductivity of the original solution, and corrects the measured value of the conductivity of the diluted solution based on the temperature of the diluted solution.

4. An automatic analyzer according to claim 1, wherein the memory unit further stores a reference temperature, the conductivity of the concentrate at the reference temperature, and correspondence information defining the relationship between the conductivity of the concentrate and temperature; and the control unit determines the temperatures of the concentrate and the diluted solution based on the measured value of the conductivity of the concentrate, the reference temperature, the conductivity of the concentrate at the reference temperature, and the correspondence information; determines the conductivity of the diluted solution at the reference temperature based on the measured value of the conductivity of the diluted solution, the temperature of the diluted solution, the reference temperature, and the correspondence information; and sets the conductivity of the diluted solution at the reference temperature as the correction value for the conductivity of the diluted solution.

5. An automatic analyzer according to claim 1, wherein the memory unit further stores a correction formula for correcting the measured value of the conductivity of the diluted solution for each conductivity of the undiluted solution, and the control unit identifies the correction formula based on the measured value of the conductivity of the undiluted solution, and corrects the measured value of the conductivity of the diluted solution based on the identified correction formula and the measured value of the conductivity of the diluted solution.

6. An automatic analyzer according to claim 1, wherein the memory unit further stores a first abnormal range in which the conductivity is higher than the normal range, or a second abnormal range in which the conductivity is lower than the normal range, and the control unit, when the corrected value of the conductivity of the diluted liquid is not within the normal range, determines the type of abnormality based on whether the corrected value of the conductivity of the diluted liquid is within the first abnormal range or whether it is within the second abnormal range.

7. An automatic analyzer according to claim 6, further comprising a plurality of electromagnetic valves that open and close the flow paths, and wherein the control unit determines which electromagnetic valve has malfunctioned.

8. An automatic analyzer according to claim 1, wherein the conductivity measuring unit measures the conductivity of the diluted liquid each time the diluted liquid is supplied to the flow path by the liquid delivery mechanism.

9. An automatic analyzer according to claim 8, wherein the conductivity measuring unit has a measurement circuit and a discharge circuit, and each time the conductivity of the diluted solution is measured, the discharge circuit releases electric charge from a capacitor in the measurement circuit.

10. An automatic analyzer according to claim 8, wherein the original liquid is a detergent, and further comprising an ejection mechanism for ejecting the diluted liquid into a cell, and wherein the control unit, when it is determined that the conductivity of the diluted liquid is abnormal, makes subsequent analysis using the cell into which the diluted liquid to be judged has been ejected impossible, while allowing analysis using other cells.

11. An automatic analyzer according to claim 10, further comprising a display unit for indicating an abnormality, wherein the control unit, when the conductivity of the diluted solution is determined to be abnormal a predetermined number of times in succession, makes analysis using other cells impossible and outputs a message to the display unit indicating this.

12. An automatic analyzer according to claim 2, wherein the memory unit stores the threshold value at a reference temperature and correspondence information defining the relationship between the conductivity of the concentrate and the threshold value, and the control unit corrects the threshold value at the reference temperature based on the measured value of the conductivity of the concentrate and the correspondence information.

13. An abnormality determination method for determining whether or not there is an abnormality in a liquid supplied to a flow path of an automatic analyzer, comprising the steps of: a conductivity measurement unit measuring the conductivity of an undiluted liquid; a conductivity measurement unit measuring the conductivity of a diluted liquid; a control unit correcting the measured value of the conductivity of the diluted liquid based on the measured value of the conductivity of the undiluted liquid; and a control unit determining whether or not there is an abnormality based on the corrected value of the conductivity of the diluted liquid and a threshold value.

14. An abnormality determination method according to claim 13, wherein the control unit corrects the threshold value in place of the measured value of the conductivity of the diluted solution, and determines whether or not an abnormality exists based on the measured value of the diluted solution and the corrected value of the threshold value in place of the corrected value of the conductivity of the diluted solution and the threshold value.

15. A program that causes a computer provided in an automatic analyzer or a computer connected to said automatic analyzer to function as: a correction unit that corrects the measured value of the conductivity of the diluted solution based on the measured value of the conductivity of the undiluted solution; and an abnormality determination unit that determines whether or not an abnormality exists based on the corrected value of the conductivity of the diluted solution and a threshold value.

16. A program according to claim 15, wherein the correction unit corrects the threshold value in place of the measured value of the conductivity of the diluted liquid, and the abnormality determination unit determines whether or not an abnormality exists based on the measured value of the diluted liquid and the corrected value of the threshold value in place of the corrected value of the conductivity of the diluted liquid and the threshold value.

Images