JP2000275207A - Clinical electrolyte measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To omit the updating of a calibration curve and to suppress the consumption quantity of a reagent for calibration when the reliability of an electrode and a device is secured in a stable state by judging calibration implementation propriety before calibration is actually made. SOLUTION: When the electrolyte concentration in a specimen is automatically measured by an ion selective electrode provided on the measurement section 15 of a clinical electrolyte concentration analyzer in this measuring method, a CPU 20 measures specific samples (blood serum low concentration calibrated liquid, blood serum high concentration calibrated liquid, urine low concentration calibrated liquid, urine high concentration calibrated liquid) with a calibration curve and judges whether calibration should be made or not this time based on the obtained measurement values.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention mainly relates to a method for measuring the electrolyte concentration in a sample by using a clinical electrolyte concentration analyzer equipped with a flow type measuring cell equipped with an ion selective electrode of sodium, potassium, chlorine, calcium, etc. It relates to a method of measuring.

[0002]

2. Description of the Related Art Conventionally, when measuring the electrolyte concentration of a sample such as serum or urine, calibration is performed at arbitrary time intervals before the sample measurement. This arbitrary time interval depends on the electrode characteristics, device performance, and the like.
About once a day is common.

In the above calibration, two types of calibration solutions having different concentrations are prepared for each sample type (serum, urine, etc.), and these two calibration solutions are prepared.
The calibration is performed by updating the calibration curve (Nernst slope) based on the measurement result of the measurement using the type of calibration solution. At that time, the electromotive force data of each calibration solution, which is data necessary for calculating the calibration curve (Nernst slope), is measured a plurality of times to ensure reliability, and the average value of the obtained plurality of measurement data or The average value of the measurement data excluding the minimum value and the maximum value is used for updating. The calibration curve updated in this manner is used as a calibration curve (Nernst slope) until the next calibration, and the electrolyte concentration (ion concentration) is calculated using the calibration curve.

[0004] In the above prior art, data drift occurs or data accuracy deteriorates during measurement under the premise that the ion selective electrode and the clinical electrolyte concentration analyzer become unstable with time. In order to avoid this, calibration is performed to update the calibration curve at regular time intervals. that time,
Since the measurement is performed a plurality of times for each calibration solution in order to improve the reliability, the reagent is consumed by (type of calibration solution) × (number of measurements).

[0005]

In recent years, ion selective electrodes and clinical electrolyte concentration analyzers have become remarkably stable as compared with the previous ones. Excessive reliability is ensured, and calibration is always performed exclusively at fixed time intervals, resulting in waste of reagent consumption. In addition, although the required measurement accuracy and the number of sample requests differ for each sample type (for example, serum and urine), it is necessary to perform calibration for both serum and urine samples if there are any. Will happen. Furthermore, in general, the number of sample requests for serum samples is significantly larger than the number of sample requests for urine samples. For example, in small and medium-sized hospitals where the number of sample particles per day is small, 50 samples of serum per day are required. If a request for five urine samples is received, the amount of reagent consumed for calibration of urine may be equal to or greater than the amount of reagent consumed for an actual sample, resulting in an increase in cost.

[0006] Japanese Patent Laid-Open No. Hei 6-1994 discloses a method of relatively inexpensively calibrating using a substitute calibration solution such as pooled serum.
Although it is proposed in Japanese Patent Publication No. 186150, even if this method is used, the number of times of calibration does not change, and it is difficult to reduce the running cost associated with replacement of the calibration solution and measurement for calibration.

[0007] The present invention provides a method for determining whether calibration can be performed or not before actually performing calibration, so that if the ion selective electrode or the clinical electrolyte concentration analyzer is in a stable state and there is no risk of losing reliability, calibration is performed. An object of the present invention is to reduce the amount of reagent consumed for calibration by omitting updating of a line.

[0008]

For this purpose, a first aspect of the present invention relates to a method for automatically measuring an electrolyte concentration in a sample by an ion-selective electrode of a clinical electrolyte concentration analyzer. A specific sample is measured using a calibration curve updated at the time of calibration, and it is determined whether or not to perform calibration this time based on a measurement result of the measurement.

According to a second aspect of the present invention, when it is determined that calibration is not to be performed this time based on the measurement result of the specific sample, the execution time of the determination is stored and the execution time is displayed. Is displayed.

In a third aspect of the present invention, when it is determined that calibration is to be performed this time based on the measurement result of the specific sample, two or more types of calibration solutions are automatically used for each calibration solution. It is characterized in that the measurement is performed at least once and the calibration curve is updated based on the measurement result of the measurement.

According to a fourth aspect of the present invention, the set value used for determining whether or not to perform the calibration is determined so that the set value is set to a value that ensures the measurement accuracy required for the sample. It is characterized by setting individually for each.

[0012]

In the first invention, when the electrolyte concentration in the sample is automatically measured by the ion selective electrode of the clinical electrolyte concentration analyzer, the calibration curve (Nernst slope) updated at the previous calibration is used. When it is determined that the ion selective electrode or the clinical electrolyte concentration analyzer is in a stable state based on a measurement result obtained by measuring a specific sample (for example, a plurality of types of standard solutions with known concentrations) one by one by using The calibration curve is not updated, and the sample is measured using the calibration curve.

In the second invention, even when it is determined that calibration is not to be performed this time based on the measurement result of the specific sample, the execution time of the determination is stored and displayed on the display means.

In the third invention, when it is determined that the calibration is to be performed this time based on the measurement result of the specific sample, the measurement is automatically performed at least once for each of the two or more types of calibration solutions, The calibration curve is updated based on the measurement result of the measurement.

In the fourth invention, the set values used for determining whether or not to perform the calibration include, for example, when serum and urine are used as samples, the measurement accuracy required for serum and urine are required. Values individually set for each sample type are used so that a high measurement accuracy is ensured.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a clinical electrolyte concentration analyzer used for carrying out the clinical electrolyte measurement method according to the first embodiment (and the second embodiment) of the present invention. This clinical electrolyte concentration analyzer measures the concentration of an electrolyte in which serum and urine coexist, for example.

In FIG. 1, reference numeral 1 denotes a calibration solution set table. The calibration solution set table 1 has a specific sample (low serum concentration) corresponding to each of the two types of samples (serum and urine) used in the present embodiment. Calibration cups 2 to 5 each containing a calibration solution, a serum high concentration calibration solution, a urine low concentration calibration solution, and a urine high concentration calibration solution are arranged. By moving the sample probe 7 relative to the calibration cups 2 to 5 vertically and horizontally by the probe transfer means 6 and rotating the sample probe 7 in the axial direction, the calibration liquid in each calibration cup is aspirated. The suctioned calibration liquid can be discharged to the dilution tube 8.

In FIG. 1, reference numeral 9 denotes a container for storing an internal reference liquid.
a and an internal reference liquid discharge mechanism 10 comprising a three-way valve 10b
Can be discharged from the internal reference liquid discharge nozzle 11 into the dilution pipe 8. Reference numeral 12 denotes a container for accommodating the diluent. The diluent in the container 12 is driven from the diluent discharge nozzle 14 into the dilution pipe 8 by driving an internal reference liquid discharge mechanism 13 including a syringe 11a and a three-way valve 11b. Can be discharged.

In FIG. 1, reference numeral 15 denotes a measuring unit, and the measuring unit 15 is provided with an ion selection electrode (not shown) for sodium, potassium, chlorine and the like. The dilution tube 8
The liquid discharged inside is sucked by driving the test liquid suction pump 16 and is discharged into a waste liquid container (not shown). At this time, when the liquid passes through the measuring section 15, a reference liquid (hereinafter referred to as REF liquid) is supplied from the container 18 to the measuring section 15 via the two-way valve 17, so that the reference liquid (hereinafter referred to as REF liquid) is generated at each ion selection electrode. Power measurements can be made.

In FIG. 1, reference numeral 20 denotes a CPU 20 provided for controlling the operation of the probe transfer means 6 and the like. In addition to the probe transfer means 6 and the like, the CPU 20 is connected to a monitor 21 as a display means, an input means (keyboard or the like) 22, and a sample transfer turret 23 used in a second embodiment described later. .

Next, the calibration operation of the clinical electrolyte concentration analyzer according to the first embodiment including the determination as to whether or not calibration is to be performed is shown in FIG.
This will be described with reference to FIG. FIG. 2 shows a CPU according to the first embodiment.
4 is a flowchart illustrating a control program of calibration control including a determination as to whether or not calibration can be performed, which is executed by the control unit of FIG. This control program is executed by the CPU 20 using a “calibration start command”.
Fires when is selected.

In FIG. 2, first, at step 51,
By driving the internal reference liquid discharge mechanism 10, the internal reference liquid in the container 9 is transferred from the internal reference liquid discharge nozzle 11 to the dilution pipe 8.
The internal reference liquid is sucked to the measuring unit 15 by driving the test liquid suction pump 16 to perform priming.

In the next step 52, it is determined whether or not calibration can be performed using the following urine high concentration calibration solution. That is, first, the sample probe 7 is relatively moved in the vertical and horizontal directions by the probe transfer means 6 and is rotated in the axial direction to aspirate the urine high concentration calibration liquid in the calibration cup 5. The urine high-concentration calibration liquid is discharged by being moved onto the dilution tube 8, and at the same time,
By driving the diluting liquid discharge mechanism 11, the diluting liquid is discharged from the diluting liquid discharge nozzle 14 into the dilution pipe 8 to perform dilution. Next, the calibration liquid for high-concentration urine diluted in the dilution tube 8 is appropriately stirred by a stirring mechanism (not shown), and then sucked and held by the test solution suction pump 16 to the measuring unit 15. The electromotive force is measured by a flow cell type ion selective electrode provided in the inside. Here, as the above-mentioned ion selection electrode, an electrode in which a type corresponding to the measurement item is appropriately combined is used. Next, the electromotive force data obtained by the above measurement is amplified by an amplifier (not shown) in the CPU 20 and converted into digital data by an A / D converter (not shown), and then the calibration curve (Nernst slope) updated at the previous calibration is obtained. ) Is used to calculate a measured value indicating the calibration solution concentration. Thereafter, the CPU 20 determines whether or not the measured value is within a range of a set value serving as an index for determining whether or not calibration can be performed. If the measured value is within the range (OK), the process proceeds to step 53;
If it is out of the range (NG), the process proceeds to step 54.

In step 53, it is determined whether or not calibration is to be performed using the urine high-concentration calibration solution in the same manner as in step 52 described above. At this time, if the measured value obtained by the electromotive force measurement on the urine low-concentration calibration solution in the calibration cup 4 is within the range of a set value serving as an index for determining whether or not calibration can be performed (OK), the process proceeds to step 55; If it is out of the range (NG), the process proceeds to step 54.

Table 1 shows an example of the concentration of a specific sample corresponding to each of the two types of samples (serum and urine) used for determining whether or not calibration can be performed in steps 52 and 53.

[0026]

[Table 1]

Table 2 shows an example of a preset set value serving as an index for determining whether or not the calibration can be performed.

[0028]

[Table 2]

The set value is a measured value (R1) of the sample.
Is set individually for each sample type (serum, urine) so that the measurement accuracy required for the measurement is ensured. Is suppressed, and the consumption of the reagent for calibration is reduced. The above set values can be arbitrarily changed. For example, if the user requests that the calibration curve be updated more importantly than the reduction in the consumption of reagents for calibration, the monitor 21 as a display means is used. To the setting screen, and input means 2 on this setting screen.
If 0 is input to the set value according to 2, the calibration curve will always be updated as in the prior art.

In the determination of whether or not the calibration can be performed in steps 52 and 53, the process proceeds to step 54 when the measured value is out of the range of the set value serving as an index of the determination of whether or not the calibration is performed. Using the high-concentration calibration solution for urine and the low-concentration calibration solution for urine used in the above, the measurement is automatically performed at least once, and the calibration curve (Nernst slope) of the urine is updated based on the obtained measured values. .

On the other hand, in step 55 in which the measured value falls within the range of the set value serving as an index for determining whether or not calibration can be performed in both of the determination of whether or not to perform calibration in the above steps 52 and 53, the CPU 20 selects an ion. Since the electrode and the clinical electrolyte concentration analyzer were determined to be in a stable state, the calibration curve for urine (Nernst slope) was not updated this time, and the calibration curve updated during the previous calibration was used. It shall be used as it is. However, the execution time of the above-described calibration execution determination is stored in the clinical electrolyte concentration analyzer, and data relating to the execution time (for example, including the year, month, day, and time) is used as data relating to the calibration curve. At the same time, it is displayed on the monitor 21 as a display means so that the operator can recognize it.

In the next steps 56 to 59, calibration control for serum is performed. In this case, in step 56, a serum high-concentration calibration liquid is aspirated in place of the urine high-concentration calibration liquid aspirated in step 52, and in step 57, instead of the urine low-concentration calibration liquid aspirated in step 53, serum is used. The calibration solution for low concentration is aspirated, but otherwise the same processing as the calibration control for urine in steps 52 to 55 is performed. Table 3 shows an example of the display of the calibration curve and the data on the execution time of the calibration execution determination in the steps 55 and 59 (the ones marked with * in Table 3 are not updated from the previous values). With this display, it is possible to distinguish between a case where the calibration curve is updated and a case where the calibration curve is not updated, and since the execution time of the last (this time) calibration execution availability determination can be determined regardless of whether or not the calibration curve has been updated, the operator can check the next time. This is a guide for estimating the timing of the determination of whether or not the calibration can be performed. Further, in this embodiment, the CPU 20 stores the days of the week when no analysis is scheduled (for example, Saturday and Sunday in Table 3), holidays, and the New Year's holiday, so that the analyzer does not judge whether or not calibration can be performed. Control to temporarily suspend operation is also performed to eliminate waste of operation.

[0033]

[Table 3]

The above-described calibration control for urine and calibration control for serum are performed when both urine and serum are used as a sample, but when only urine is used or only serum is used. In this case, only the relevant calibration control is executed, and unnecessary calibration control is omitted. Then, after the inside of the dilution tube 8 is washed in the next step 60, the present control is ended.

According to this embodiment, step 52, step 53, and step 56 are performed based on the measurement result of the specific sample (urine, serum) using the calibration curve updated at the time of the previous calibration.
If it is determined that the calibration is not to be performed this time according to the determination as to whether or not to perform the calibration in step 57, it means that the ion selection electrode and the clinical electrolyte concentration analyzer are determined to be in a stable state. Since the calibration curve is not updated, the consumption of the reagent is calculated in steps 52 and 5 described above.
One measurement is performed for each of 3, 56, and 57 specific samples, and the consumption of reagents for calibration can be significantly reduced. Further, in this case, since the data on the execution time of the calibration execution determination is displayed on the monitor 21, the operator who sees the data can predict the time of the next calibration execution determination.

Also, according to the present embodiment, when it is determined that the current calibration is to be performed based on the measurement results of the specific samples (urine and serum) in step 52 and step 53, and in step 56 and step 57, whether or not to perform the calibration. , Two measurements (high concentration and low concentration) of each of the specific samples (urine and serum) are automatically measured once, and the calibration curve is updated based on the measurement results. Therefore, the work of setting the calibration solution and the work of updating the calibration curve (Nernst slope) are not required, and the usability of the clinical electrolyte concentration analyzer is improved.

Further, according to the present embodiment, the set value serving as an index for determining whether or not to perform calibration is determined for each sample type so that the measurement accuracy required for serum and the measurement accuracy required for urine are ensured. Since the individually set values are used, updating of the calibration curve particularly for urine is suppressed, and the consumption of reagents for urine calibration can be suppressed.

In the first embodiment, the specific sample used for the determination as to whether or not to carry out the calibration is also used as the calibration solution. Alternatively, two types of known concentrations at the positions not shown in FIG. A control sample may be set, and the same calibration determination as described above may be performed using the control sample. Further, the number of specific samples used for determining whether or not calibration can be performed is not limited to two types, and three or more types of specific samples may be used. Also, the number of times the calibration curve was not updated
The count value may be counted in U20, and the count value may be displayed on the monitor 21 as the display means. Also,
At this time, the calibration may be forcibly performed when the count value reaches a predetermined number of times, so that the calibration data may be managed or refreshed so that stable high-precision analysis may be performed.

Further, the display of the data relating to the execution time of the determination as to whether or not the calibration can be performed may be such that the previous data is displayed in addition to the present data. Further, it is preferable to display data of about 10 times in the past, including this time, in order to check the deterioration of the electrode. The display of the data on the execution time of the calibration execution determination may be continued until the next calibration execution determination is started. Also,
Until the next calibration is performed, it is preferable to always display (or recall from the memory when necessary). Further, instead of displaying the data relating to the execution time of the above-described calibration execution determination (or in addition to displaying the data relating to the execution time of the above-described calibration execution determination), a buzzer or the like (not shown) may indicate that “the calibration was not performed”. May be notified, or a mark, a color, or the like indicating that “calibration has not been performed” may be displayed on the monitor 21 so that the operator can recognize it. Further, even when it is determined that the calibration is to be performed this time, data regarding the execution time of the above-described calibration execution availability determination may be displayed.

The calibration control including the determination as to whether or not to perform calibration according to the first embodiment is generally applied to an operation performed by an operator before measuring the electrolyte concentration of a sample (patient sample). This calibration control logic can also be applied to a control sample measurement operation for checking the state of the ion selection electrode and the clinical electrolyte concentration analyzer while actually measuring the electrolyte concentration of the patient sample. In this case, the calibration control can be applied to a case where a diluted calibration solution that does not require a diluting solution is used as the calibration solution. A case where the present invention is applied to the control sample measurement operation will be described below as a second embodiment.

In the second embodiment, in the clinical electrolyte concentration analyzer shown in FIG. 1, a sample transport turret 23, a large number of sample containers 24 set on the sample transport turret 23, The sample stored in the test sample container 24 is used, and the sample includes a patient sample and two types of control samples. In addition, when performing the calibration execution determination using the control sample irregularly during the measurement of the patient sample, although not shown, the set positions of the containers 2 to 5 containing the respective calibration liquids are not shown. It is desirable to provide a lid that is not easily subject to liquid concentration or denaturation, and an opening / closing mechanism and a cooling mechanism for the lid.

Next, an outline of a calibration operation including determination as to whether or not calibration is to be performed by the clinical electrolyte concentration analyzer according to the second embodiment will be described. This operation is interrupted during the measurement of the patient sample, and is basically similar to the operation of the first embodiment. First, after setting a large number of sample containers 24 including a sample container accommodating a patient sample and two types of control samples in the sample transport turret 23 of FIG. 1, the sample sample container stopped rotating at the sample suction position. The operation of aspirating the control sample from 24 and performing one measurement is repeated twice. Next, similarly to the first embodiment, the CPU 20
The measured value of each control sample is within (OK) or out of range (N) of the set value serving as an index for determining whether or not calibration can be performed.
G). In addition, as the above set value,
The configuration shown in Table 2 used in the first embodiment may be expanded to use a configuration provided with a set value for each calibration solution and a set value for each control sample.

In the above determination, the measured value of each control sample falls within the range of the set value (O
In the case of K), since it is determined that the ion selection electrode and the clinical electrolyte concentration analyzer are in a stable state, the calibration curve (Nernst slope) is not updated this time. On the other hand, when the measured value of each control sample is out of the range of the set value serving as an index for determining whether or not calibration can be performed (NG),
Using two kinds of calibration solutions set in advance, namely, a high concentration calibration solution for urine and a low concentration calibration solution for urine, or a high concentration plate positive solution for serum and a low concentration calibration solution for serum, each calibration solution is used. Is measured one or more times, and the calibration curve (Nernst slope) is updated based on the measured values. In this way, the concentration of the electrolyte in the sample is measured based on the result obtained by executing the determination on whether or not the calibration is performed, regardless of whether or not the calibration curve is updated.

According to this embodiment, the same operation and effect as those of the first embodiment can be obtained.

In the second embodiment, when the measured value of each control sample is out of the range of the set value in Table 2 which is an index for determining whether or not calibration can be performed, judgment is made based on the degree of the deviation, and calibration is performed. The number of measurements with each calibration solution used for updating the line may be determined. In this case, for example, as shown in Table 4, when the measured value (R2) of each control sample is within the range of the set value in all the measurement items, the number of measurements for updating the calibration curve is increased by one each. And the measured value (R
If 2) is out of the range of the set value even for one measurement item, the number of measurements for updating the calibration curve is measured n times (for example, n = 4), and the average of the obtained measurement values is measured. The calibration curve shall be updated using the values.

[0046]

[Table 4]

In the second embodiment, when the result of updating the calibration curve indicates an abnormality, it is determined whether or not the calibration curve is abnormal due to deterioration of the electrode or an artificial setting error of the specific sample. In addition, if it is determined that there is an abnormality, the control program of FIG. 1 may be changed so that the logic is such that the calibration curve is always updated at the next determination of whether or not to perform calibration. The calibration curve may be recognized as the previous calibration curve, and the calibration curve may be used to conform to the control program of FIG. 1 described above.

Further, in the above-described second embodiment, a case has been described in which a clinical electrolyte concentration analyzer using a flow cell type ion-selective electrode is used. After transporting the various rod-shaped electrodes thus obtained and immersing them directly in the sample container 24 and the calibration cups 2 to 5, a clinical electrolyte concentration analyzer for cleaning in a washing tank (containing a washing liquid) is appropriately provided. It may be used.

[0049]

According to the first aspect of the present invention, when a specific sample (for example, a plurality of standard solutions of known concentrations) is measured, for example, once by using the calibration curve (Nernst slope) updated at the time of the previous calibration. If it is determined from the measurement results that the ion selective electrode or the clinical electrolyte concentration analyzer is in a stable state, the calibration curve is not updated, thus reducing the consumption of reagents required for calibration and impairing reliability. It is possible to analyze the electrolyte concentration of the sample without any need.

According to the second aspect of the present invention, even when it is determined that calibration is not to be performed this time, the execution time of the determination is stored and displayed on the display means. It is possible to predict the timing of the execution availability determination.

According to the third aspect of the invention, when it is determined that the calibration is to be performed at this time, one or more measurements of each of the two or more kinds of calibration liquids are automatically performed, and a calibration curve based on the measurement result of the measurement is automatically obtained. Since the updating is performed, the work of setting the calibration liquid and updating the calibration curve (Nernst slope) becomes unnecessary.

According to the fourth aspect of the invention, the set value used for the determination as to whether or not to perform calibration is individually set for each sample type so as to ensure the required measurement accuracy for the sample. Updating of the calibration curve for the other sample (for example, urine when serum and urine is used as the sample) is suppressed, and the consumption of reagents required for calibration of the sample with the lower required measurement accuracy is suppressed. be able to.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a clinical electrolyte concentration analyzer used for carrying out clinical electrolyte measurement methods according to first and second embodiments of the present invention.

FIG. 2 is a flowchart illustrating a control program of calibration control including a determination as to whether or not to perform calibration in the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Calibration liquid set table 2-5 Calibration cup 6 Probe transfer means 7 Sample probe 8 Dilution tube 9, 12, 18 Vessel 10 Internal reference liquid discharge mechanism 11 Internal reference liquid discharge nozzle 13 Internal reference liquid discharge mechanism 14 Diluent discharge nozzle 15 Measuring unit 16 Sample suction pump 17 Two-way valve 20 CPU 21 Display means (monitor) 22 Input means (keyboard etc.) 23 Turret 24 Sample container for test

Claims (4)

[Claims] When automatically measuring the electrolyte concentration in a sample using an ion-selective electrode of a clinical electrolyte concentration analyzer, a specific sample is measured using a calibration curve updated at the time of the previous calibration. A method for measuring a clinical electrolyte, characterized in that it is determined whether or not to perform calibration this time based on a measurement result. 2. When it is determined that calibration is not to be performed this time based on the measurement result of the specific sample, an execution time of the determination is stored, and the execution time is displayed on a display unit. The method for measuring a clinical electrolyte according to claim 1. 3. When it is determined that calibration is to be performed this time based on the measurement result of the specific sample, two or more types of calibration solutions are automatically used to perform measurement once or more for each calibration solution. 2. The method according to claim 1, wherein the calibration curve is updated based on a measurement result of the measurement. 4. A setting value used for determining whether or not to perform the calibration is individually set for each sample type so as to be a value that ensures measurement accuracy required for the sample. The clinical electrolyte measurement method according to claim 1, wherein: