JPH0389158A - Calibration of ion electrode for clinical chemical measurement - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. The present invention relates to a method for calibrating an ion electrode for clinical chemistry measurement that measures electrolyte concentration in a liquid sample for clinical chemistry such as human blood, and in particular to a method for calibrating an ion electrode using a body fluid for calibration. The present invention relates to a method for calibrating an ion electrode for clinical chemistry measurement, which makes it possible to accurately and inexpensively calibrate an ion electrode by appropriately knowing when it is necessary.

In the field of clinical chemistry, electrolytes in body fluids of the human body, such as ions such as sodium, potassium, and chlorine in blood, are measured using ion electrodes.

This ion electrode uses an aqueous solution (standard aqueous solution) with a known concentration of sodium ions, etc. as a standard solution for calibration, and calibrates the concentration-point for each measurement. Using an aqueous solution, it is used while further performing two-point concentration calibration, for example, once every several dozen measurements or once or several times a day.

However, if an aqueous solution called a standard aqueous solution is used as a standard solution for calibration, the response of the ion electrode is different from that of blood, so accurate calibration is not necessarily possible. When measuring sodium ions, etc. in blood, a short difference in concentration sometimes occurs between the measured concentration and the actual concentration.

Therefore, in order to eliminate such short differences in concentration, serum with known concentration (for example, standard serum certified by the Japanese Society of Clinical Chemistry,
Recently, a method has become popular in which a pooled serum unique to each medical institution is used as a calibration serum, and the ion electrode is calibrated with the serum from time to time during the calibration with the standard aqueous solution.

According to this method, accurate calibration with serum is sometimes intermixed with calibration with standard aqueous solution, which improves the reliability of ion electrode calibration, and thus improves the reliability of ion electrode measurement. By eliminating the short gap between the concentration and the actual concentration, it becomes possible to accurately measure sodium ions and the like in the blood using an ion electrode.

However, there was no good indicator as to how often serum calibration should be performed between calibrations using standard aqueous solutions to ensure improved reliability of ion electrode calibration when combined with serum calibration. For this reason, conventionally, it has been necessary to perform calibration using expensive serum quite frequently.

Therefore, an object of the present invention is to provide an ion electrode for clinical chemistry measurements that enables accurate and inexpensive calibration of ion electrodes by appropriately knowing when it is necessary to calibrate ion electrodes with body fluids such as serum. The purpose of the present invention is to provide a calibration method.

The above objects are achieved by the method for calibrating an ion electrode according to the present invention. To summarize, the present invention provides two types of electrolyte concentrations with known electrolyte concentrations in advance when calibrating an ion electrode for measuring electrolyte concentration in a clinical chemistry body fluid sample using a calibration body fluid with a known electrolyte concentration. Using a standard aqueous solution, measure the change in the electromotive force of the ion electrode per 19X and the change in the response time until a predetermined electromotive force is reached, and find out whether or not it is necessary to calibrate the ion electrode with the calibration body fluid. This is a method for calibrating an ion electrode for clinical chemistry measurement, characterized in that, after that, one calibration of the ion electrode is performed using the body fluid for calibration.

Side and 1 Examples of the present invention will be described below.

FIG. 1 is a schematic diagram showing an example of an ion electrode automatic measuring device for clinical chemistry to which the ion electrode calibration method of the present invention is applied.

As shown in FIG. 1, an ion electrode automatic measuring device 1 has a measuring cell 2 for measuring a body fluid sample for clinical chemistry such as blood. A sample flow path 4 is formed within the measurement cell 2,
A sodium ion electrode 6, a potassium ion electrode 8, and a comparison electrode 10 are arranged along the flow path 4.

A suction nozzle 12 is provided on the upstream side of the measurement cell 2,
A standard solution supply pipe 36 is connected to the middle of the suction nozzle 12 . The standard solution supply pipe 36 includes a low concentration standard solution supply pipe 3.
2a, a two-discharge solenoid valve 3 for air to which the high concentration standard solution supply pipe 34a is connected and which also takes air for cleaning the suction nozzle 12;
8 is connected.

A discharge pipe 18 is provided downstream of the measuring cell 2 and leads to a waste liquid tank 20 . Furthermore, an internal liquid supply pipe 24 connected to an internal liquid tank 22 for comparison electrode is connected to the downstream side of the measurement cell 2 .

Further, a peristaltic bomb Pa is provided between the discharge pipe 18 and the internal liquid supply pipe 24, and a peristaltic bomb Pb is provided in the middle of the standard liquid supply pipe 36.

According to the ion electrode automatic measuring device 1 as described above, the sample container 1 containing a body fluid sample for clinical chemistry, for example, blood.
4 to the suction nozzle 12 and drive the peristaltic pump Pa, the blood in the sample container 14 is transferred to the measurement cell 2.
The sample is fed into the sample flow path 4 inside the sample. Then, the sodium ion concentration in the blood is measured by the sodium ion electrode 6, and the potassium ion concentration in the blood is similarly measured by the potassium ion electrode 8.

During the measurement, the sodium ion electrode 6 and the potassium ion electrode 8 are calibrated by concentration-point calibration using one type of standard aqueous solution each time the measurement is made, as in the past.

That is, for example, by connecting the standard solution tank 32 containing a standard aqueous solution with known concentrations of sodium ions and potassium ions to the low concentration standard solution supply pipe 32a and driving the peristaltic pump pb, the standard aqueous solution is supplied into the measurement cell 2. into the sample flow path 4. Then, the sodium ion concentration of the standard aqueous solution is measured using the sodium ion electrode 6, and the sensitivity of the amplifier of the measuring device 1 to the sodium ion electrode 6 is adjusted and calibrated so that the measured concentration matches the concentration of the standard aqueous solution. Similarly, the potassium ion concentration of the standard aqueous solution is measured using the potassium ion electrode 8, and the sensitivity of the amplifier of the measuring device 1 to the potassium ion electrode 8 is adjusted and calibrated so that the measured concentration matches the concentration of the standard aqueous solution. .

In addition, by adding calibration using a high-concentration standard aqueous solution that has a higher concentration than the previous standard aqueous solution, for example, once every several dozen measurements, once a day, or several times a day, it is possible to reduce the Calibration is performed at two points: concentration and high concentration.

Calibration using a high concentration standard aqueous solution is performed by connecting a standard solution tank 34 containing a high concentration standard aqueous solution with known concentrations of sodium ions and potassium ions to the high concentration standard solution supply pipe 34a, and using a peristaltic pump Pa to
After feeding the standard aqueous solution into the measurement cell 2, the sodium ions and potassium ions in the standard aqueous solution are measured using the sodium ion electrode 6 and the potassium ion electrode 8, respectively, in the same manner as before for calibration.

The above operations are automatically performed under the control of a CPU (not shown) of the measuring device 1.

As mentioned above, if an aqueous solution called standard aqueous solution is used as the calibration standard solution, the response by the ion electrode is different from that of blood, so accurate calibration cannot always be achieved. Therefore, serum of known concentration is used for calibration. Calibration with serum is sometimes performed between calibrations with standard aqueous solutions, but how often should serum calibrations be performed between calibrations with standard aqueous solutions? Since there was no good indicator of whether improved reliability could be ensured, conventional calibration using expensive serum had to be performed quite frequently.

For this reason, in the present invention, the ion electrode automatic measurement device 1 determines when it is necessary to calibrate using serum as follows, and calibrates the sodium ion electrode 6 and potassium ion electrode 8 using serum.

That is, when the change in the sensitivity of the ion electrode to serum is large, the change in sensitivity to the standard aqueous solution is also large, and since the ion electrode cannot be accurately calibrated using the standard aqueous solution, accurate calibration using serum is required. In that case, when the change in sensitivity of the ion electrode to the standard aqueous solution is large, the change in sensitivity to serum may also be large, but when the change in sensitivity to the standard aqueous solution is small,
Ion electrodes have little change in sensitivity even with serum. Therefore, in order to reduce the number of times the ion electrode is calibrated using serum and to perform calibration using serum whenever necessary, it is necessary to calibrate the ion electrode only when there is a large change in the sensitivity of the ion electrode with respect to the standard aqueous solution. It is sufficient to determine that calibration using serum is necessary and calibrate the ion electrode using serum.

Therefore, using two standard aqueous solutions with known sodium ion concentrations, we measured the change in the electromotive force of the sodium ion electrode and the change in the response time until a predetermined electromotive force was reached per 1 pX change in the concentration of the standard aqueous solution. By determining the magnitude of the change, that is, the magnitude of the change in sensitivity of the sodium ion electrode with respect to the standard aqueous solution, it can be determined whether or not calibration of the sodium ion electrode with serum is necessary. Similarly, if you perform the same operation using two standard aqueous solutions with known potassium ion concentrations, you can determine whether or not calibration of the potassium ion electrode with serum is necessary. By using standard aqueous solutions of different concentrations, it is possible to simultaneously determine whether or not calibration of sodium ion electrodes and potassium ion electrodes with serum is necessary. The determination of whether or not it is necessary to calibrate the ion electrode using serum can be reliably determined by performing the calibration once or several times every - day.

In this ion electrode automatic measuring device 1, a sodium ion electrode is used, for example, once every several dozen blood measurements, once a day, or several times a day, using standard aqueous solutions of low and high concentrations. 6 and potassium ion electrode 8, it is only necessary to use the calibration of the two concentration points, and the concentration of sodium ion electrode 6 and potassium ion electrode 6 per 1 pX concentration change of the standard aqueous solution at that time is used. Electrode 8
The changes in the electromotive force and the response time until reaching a predetermined electromotive force are measured,
and whether or not calibration of the potassium ion electrode 8 is necessary.

Once you have learned the need to calibrate the sodium ion electrode 6 or potassium ion electrode 8 using serum as described above, use serum with known sodium ion concentration and potassium ion concentration as the calibration serum to calibrate the sodium ion electrode 6 or potassium ion electrode 8 using serum. 6 or the potassium ion electrode 8 may be calibrated.

According to this, it is possible to reduce the number of times the sodium ion electrode 6 and the potassium ion electrode 8 are calibrated using serum, and to perform calibration using serum without missing any necessary cases. Therefore, even if calibration with serum is not performed frequently, the sodium ion electrode 6 and the potassium ion electrode 8 can be used in conjunction with calibration with serum between calibrations with standard aqueous solutions.
The reliability of the calibration can be improved, and the calibration can be made at low cost.

In the above embodiments, the calibration method of the present invention is applied to an ion electrode incorporated in an automatic ion electrode measurement device for clinical chemistry. However, the present invention also applies to the case of an ion electrode that is used manually. Needless to say, it can be applied. Furthermore, although the case where the ion electrode is used for blood is shown, the present invention is not limited to this, and can also be applied to the case where the ion electrode is used for other body fluid samples for clinical chemistry such as lymph fluid and urine. It can be similarly calibrated using the same method.

As explained above, according to the calibration method of the present invention, it is possible to accurately and inexpensively calibrate ion electrodes by appropriately knowing when it is necessary to calibrate ion electrodes with body fluids such as serum. can be done.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of an ion electrode automatic measuring device for clinical chemistry to which the ion electrode calibration method of the present invention is applied. 1: Ion electrode automatic measuring device 2 Measuring cell 6: Sodium ion electrode 8: Potassium ion electrode 10: Reference electrode 14: Sample container 32. 34: Standard aqueous solution

Claims (1)

[Claims] 1) When calibrating an ion electrode for measuring the electrolyte concentration in a clinical chemistry body fluid sample using a calibration body fluid with a known electrolyte concentration, two standard aqueous solutions with known electrolyte concentrations are used in advance. Then, the changes in the electromotive force per 1 pX of the ion electrode and the changes in the response time until reaching a predetermined electromotive force are measured to determine whether or not the ion electrode needs to be calibrated using the calibration body fluid. A method for calibrating an ion electrode for clinical chemistry measurement, comprising calibrating the ion electrode using a body fluid for calibration.