JPS62240848A - Humor component assaymeter - Google Patents

Abstract

PURPOSE:To achieve a highly accurate assay, by detecting frequency of use of time of use, selecting one or more of the making of a power source, the feeding of a carrier liquid, the feeding of a calibration liquid, the feeding of a sample to be measured and the display of humor as elements. CONSTITUTION:When a power source switch 10 is turned ON, a timer 8 starts with an arithmetic processing circuit 2. A constant voltage source 5 is connected to one end of an immobilized enzyme sensor 1 while the other end thereof, to an inversion input terminal of an operational amplifier OP of a voltage conversion circuit 6. The sensor 1 reacts with glucose in a reaction tank to generate a current proportional to the value of glucose and converted into a voltage with the circuit 6, the output voltage from which is converted into a digital value with an A/D conversion circuit 7 and inputted into the circuit 2 to be stored in the data memory 11. At the same time, the circuit 2 reads in a timer value from a timer 8 to be stored in a time memory 9. Then, the circuit 2 performs an arithmetic processing of the contents of the memory 11, the memory 9 and the time correcting data memory 13 and outputs the amount of glucose in a blood sample to a display circuit 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field 1] The present invention relates to a blood a component quantifier for measuring the concentration of body fluid components, particularly blood components, contained in body fluids, urine, etc.

[Background technology 1] Measuring devices using immobilized enzyme sensors in which biocatalysts (bioactive substances) such as enzymes with molecular identification functions are immobilized on electrodes are widely used in clinical testing, food industry fields, etc.
11 It is being put into practical use in a wide range of fields.

The immobilized IlIv cord sensor has substrate specificity, reaction specificity,
Although they have excellent sensitivity and responsiveness, they generally have short lifespans and sensitivity tends to fluctuate. Therefore, deterioration over time has caused a decrease in constant precision. Furthermore, if measurements are continued using a fixed M-cord sensor that has deteriorated severely, incorrect quantification will occur.
This will cause confusion.

1 Objective of the Invention 1 The present invention has been provided in view of the above-mentioned problems, and an object of the present invention is to provide a body fluid component quantitative meter that can perform highly accurate quantitative determination by taking appropriate measures over time. It is something.

DISCLOSURE OF THE INVENTION 1 (Structure) The present invention detects use 11 times or use darkness as required by one or more of power-on, carrier liquid injection, calibration liquid injection, sample to be measured injection, and display of body fluid components, The alternative is to provide a detection means for detecting the sensitivity of the immobilized enzyme sensor using this detection signal.

(Example 1) Hereinafter, one example of the present invention will be described with reference to the drawings. FIG. 1 shows a block diagram of a body fluid component quantitative meter according to the present invention. For example, as shown in FIG. 1, in a body fluid component quantitative meter that measures glucose levels, when a power switch 10 is turned on, a timer 8 is started by an arithmetic processing circuit 2. An immobilized #element sensor 1 that reacts with glucose is installed in a reaction tank containing a carrier liquid and a blood sample, and a constant voltage source that generates a stabilized voltage of about -0.7 V is attached to one end of the immobilized enzyme sensor 1. 5 is connected, and the other end of the immobilized enzyme sensor 1 is connected to the inverting input end of the operational amplifier OP of the voltage conversion circuit 6.

The immobilized enzyme sensor 1 generates a current proportional to the glucose value in response to glucose in the reaction tank, and this electric current tI
1. i is converted into a voltage V ("iR,) by a voltage conversion circuit 6 consisting of an operational amplifier oP and a resistor R0 connected to its output terminal and one inverting input terminal. This voltage conversion circuit 6 The voltage V output from the A/D conversion circuit 7 is converted into a digital value, inputted to the arithmetic processing circuit 2, and stored in the data memory 11. At the same time, the arithmetic processing circuit 2 Read the timer value from
Stored in timer memory 9. The arithmetic processing circuit 2 performs arithmetic processing on the contents of the data memory 11, timer memory 9, and time correction data memory 13, and calculates the amount of glucose in the blood sample by 100si0. 6. The display circuit 4 outputs the glucose value of the hit to the display circuit 4. l! Converts the manually input glucose value from circuit 2 into display data,
Digital display is performed on the display 3.

Next, the measurement procedure and operation of the arithmetic processing circuit 2 in this body fluid component quantitative meter will be explained based on FIG. 2, FIG. Furthermore, Figure 2 shows the immobilized enzyme sensor J.
It is a characteristic diagram showing the relationship between the energization time and the output current.
FIG. 3 shows the output current of the immobilized enzyme sensor 1 during calibration solution injection and blood sample injection. FIG. 4 shows an internal correction 70-chart to be described later, and FIG. 5 shows a 184-chart.
It is a figure which shows the relationship between time III and sensitivity in explanation of a figure.

First, when the power switch 10 is turned on, the arithmetic processing circuit 2 starts the timer 8. Immobilized enzyme sensor 1 is placed in a reaction tank containing a predetermined amount of carrier g.

At this time, the output current of the immobilization sensor 1 becomes level P, as shown in FIG. This output current P is converted into a voltage by the voltage conversion circuit 6, further converted into a digital value by the A/D conversion circuit 7, and inputted to the arithmetic processing circuit 2 to be stored in the data memory 11. A predetermined amount of the calibration solution is injected into the reaction tank containing the 97 solution. As a result,
The immobilized enzyme sensor 1 responds to a predetermined amount of glucose in the calibration solution, resulting in an output level of Q. The output current Q of the immobilized enzyme sensor 1 is converted into a digital value, input to the arithmetic processing circuit 2, and stored in the data memory 11 in the same way as described above. At the same time, the value To of the timer 8 at this time is stored in the timer memory 9. Next, when the first blood sample is additionally injected into the reaction tank, the immobilized enzyme sensor 1 becomes fIS1.
Reacts and immobilizes glucose in the blood sample of the mouth #
The output current of the cable sensor 1 has a level R1 corresponding to the sum of the glucose value in the predetermined amount of carrier liquid, the calibration liquid at a predetermined temperature, and the glucose value of the first blood sample.

The output current of the immobilized enzyme sensor 1 is similarly input to the arithmetic processing circuit 2 and stored in the data memory 11. At the same time, the value TR of the timer 8 at this time is stored in the timer memory 6. The output current (i.e., sensitivity) of the immobilized enzyme sensor 1 in response to a constant glucose level gradually deteriorates with respect to the energization time, as shown in FIG. Time correction data memory 1
3 stores the unexamined patent correction function for this sensitivity, and the arithmetic processing circuit 2 corrects the current value l stored in the data memory 11 using the current correction function [In4 Figures and V 5th R1), III Normally, a linear Kintetsu function such as Δ1B/3T is used as the positive function. Here, A is the output value at T, B is the deterioration rate (constant), and -T is the change from the calibration time. At this time, the correction value R' is expressed by the following equation.

R' = R + B (TRTo) The arithmetic processing circuit 2 uses the correction value R' and the data P and Q stored in the data memory 11 to calculate the arithmetic expression ((R,' -Q)/(Q-P)l·S. Calculate the glucose value of the blood sample per 100 samples. S is the pre-stored calibration [100 - is the glucose value per sample, usually 5=100. The determined glucose value is displayed as The blood sample is sent to the circuit 4, and the glucose value of the first blood sample is digitally displayed on the display 3.

Subsequently, when a second blood sample is additionally injected, the output level of the immobilized enzyme sensor 1 becomes the sum R2 of the current at the end of the first measurement and the current in response to glucose in the second blood sample. Become.

Similarly to the above, it is converted into a dinotal value by the A/D conversion circuit 7, inputted to the arithmetic processing circuit 2, and then input to the data memory 11.
is stored in At the same time, the value of timer 8 is stored in timer memory 9. Similarly to the first time, the data R2 in the data memory 11 is corrected to the current values R and I of the reference energization time, and is 10010. The glucose value of each blood sample is recorded. The glucose value is displayed on the display 3 via the display circuit 4. Considering the nth blood sample, the glucose value is calculated using the following calculation formula in the same manner as in the above fabrication.

((Rn'-R++-+')/(Q-P)l・S) When the measurement is finished and the power is turned off, the arithmetic processing circuit 2
stores the calculated values Q and P and the value of the timer 8 in the timer memory 9.

When the power is turned on again, the arithmetic processing circuit 2 stores the value of the timer memory 9 in the timer 8, and the timer 8 starts from that value. Therefore, the timer 8 always indicates the total energization time of the immobilized enzyme sensor 1. For measurement after turning on the power again, if the current value when immersed in the carrier liquid is R1, and the current value when injecting the blood sample is 1 < 2, the glucose value can be similarly calculated using the calculation formula (% formula %). . Furthermore, R,'
, R,' are values after normal time correction. Furthermore, when the immobilized enzyme sensor 1 is replaced, the timer reset switch 12 is turned on to reset the timer 8, and the times when the immobilized enzyme sensor 1 is opened when energized are counted again. The timer 8, timer memory 9, etc. constitute a detection means for detecting the sensitivity of the immobilized enzyme sensor 1.

*In Fig. 3, a indicates injection of the calibration solution, I) indicates the first blood sample injection, C indicates the second blood sample injection, and d indicates the third blood sample.

In this way, the timer 8, which indicates the total energization time of the immobilized enzyme sensor 1, determines the output current, that is, the sensitivity, of the immobilized enzyme sensor 1 when the current is opened at a certain time, as shown in FIG. Therefore, by replacing the immobilized enzyme sensor 1 that has been used for a predetermined period of time, it is possible to obtain an accurate glucose value that does not include errors due to deterioration due to the energization time without frequent calibration. be.

(Example 2) Figure in6 is a 70-chart showing Example 2. In Example 1, before or after displaying the glucose value, the energization open TR stored in the timer memory 9 is displayed on the display 3. This is how it is displayed. This results in
The user can know the total energization time of the immobilized enzyme sensor 1, and the degree of deterioration of the immobilized enzyme sensor 1 is 11.
9. It helps to know when to replace the fixed 1511 sensor 1. Moreover, if the time from the time of calibration is displayed, the time from the time of calibration can be seen, and it is even better because the time of calibration can be known.

(Example 3) FIGS. 7 and 8 show a 70-chart and an operation explanatory diagram of Example 3. In Example 1, the arithmetic processing circuit 2 calculates the difference between the calibrated time To and the measured time T. is calculated, and the change in sensitivity B (TRTo) is calculated. When it becomes larger than the predetermined value α stored in the time correction data memory 13, a signal is sent to the display circuit 4 to prompt the user to calibrate, and the display 3 It is designed to display a specific display. As shown in the first embodiment, the time correction function is a linear function such as A+BdT, and as the time difference becomes larger, the correction error increases. Therefore, when the value exceeds a certain predetermined value α, by recalibrating, the value of QP can be brought closer to the measurement sensitivity, and accuracy can be maintained.

(Embodiment 4) FIGS. 9 and 10 show a 70-chart and an operation explanatory diagram of Embodiment 4, and show the time T calibrated by the arithmetic processing circuit 2. and the measured time TR, and calculate the sensitivity change B(T
R-To) is calculated and compared with the predetermined value α1° α2 stored in the time correction data memory 13. For example, if the change in sensitivity is smaller than a, it is determined “for accuracy reasons”, and if it is larger than α1 and smaller than α2, it is determined that "Accuracy medium", if it is greater than a2, it is set as [accuracy lower 1], and before displaying the glucose value, a signal is output to the display circuit 4 to display any one of "high, medium, low" as the grade, and the display 3. This allows the user to know the accuracy and
It is possible to know when to calibrate the immobilized enzyme sensor 1 and when to replace it.

(Embodiment 5) FIG. 11 shows a 70-chart of Embodiment 5, in which the arithmetic processing circuit 2 calculates the measured time 'R and time correction data/Mori 1.
3, and if rR>α, a signal indicating that measurement is impossible is output to the display circuit 4, and a specific display is made on the display 3. As shown in Fig. 2, the immobilized enzyme sensor 1 enters an unstable region after opening at a certain energization time, and the reaction is not stable, so there is no reproducibility and accurate values cannot be measured.Therefore,
It is necessary to replace the immobilized enzyme sensor 1. By replacing the immobilized enzyme sensor 1 based on this display, accurate measurements can be made again. When replaced, the timer 8 is reset by turning on the timer reset switch 12.

In the above embodiment, the timer memory 9 and the data memory 1
1. Although the time correction data memory 13 was separate, they can be integrated into one by using a single-chip CPU.

Further, in the above embodiment, a sensor for measuring glucose values has been described, but by changing the immobilized enzyme sensor 1, other body fluid components such as cholesterol and uric acid can be detected in the same way.

[Effects of the Invention 1] As described above, the present invention enables one of the following: power-on, carrier liquid injection, calibration liquid injection, measurement sample injection, and body fluid component display.
The device is equipped with a detection means that detects the number of times or usage time of the immobilized enzyme sensor based on two or more factors, and detects the sensitivity of the immobilized enzyme sensor based on this detection signal. By detecting the time,
It is possible to know the deterioration of the immobilized enzyme sensor over time.
Therefore, by appropriately replacing the immobilized enzyme sensor, highly accurate quantification can be performed. This has the advantage of not requiring quantitative measurements.

[Brief explanation of drawings]

FIG. 1 is a block diagram of Example 1 of the present invention, FIG. 2 is a characteristic diagram showing the relationship between the output of the immobilized enzyme sensor and the energization time, and FIG. 3 is an explanatory diagram of the operation by injection of the rrrLa sample as described above. , FIG. 4 is the 70-chart of the same as above, plS5 is an explanatory diagram of the same as the above, and FIG. 6 is the 70- of the same as the embodiment 2.
The chart, FIG. 7, and fIS 8 are the same as Example 3-7.
0-chart and operation explanatory diagram, tIS9 diagram and FIG. 10 are the 70-chart and operation explanatory diagram of the fourth embodiment, and FIG. 1 shows an immobilized enzyme sensor. Agent Patent Attorney Ishi 1) Ai 7 Figure 2 Figure 3 JIU5H] Procedural amendment (voluntary) May 29, 1985 Patent H No. 85433 of 1986 2, Title of invention: Body fluid component quantitative meter 3; Person making the amendment Relationship to the matter Patent applicant Address 1048 Kadoma, Kadoma City, Osaka Prefecture Name (58
3) Matsushita Electric Works Co., Ltd. Representative Sadao Fujii 4, agent postal code 530 5, date of amendment order [11 of the attached drawings @ Figure 4, Figure 6, Figure 7, Figure 9 and Figure 11] Correct the figure as shown in the attached sheet.

Claims (6)

[Claims] (1) Detect the number of times or time of use based on one or more of the following factors: power-on, carrier liquid injection, calibration liquid injection, sample to be measured, and display of body fluid components, and this detection signal is used to detect the sensitivity of the immobilized enzyme sensor. A body fluid component quantitative meter equipped with a detection means for detecting. (2) The detection signal detects changes in the sensitivity of the immobilized enzyme sensor during calibration and the sensitivity of the immobilized enzyme sensor during body fluid measurement, and the changes are corrected to quantify the body fluid components. A body fluid component quantitative meter according to claim 1. (3) The body fluid component quantitative meter according to claim 2, characterized in that the time of use or the number of times of use is displayed based on the detection signal. (4) The body fluid component quantitative meter according to claim 2, further comprising a display function that prompts the user to recalibrate using a detection signal. (5) The body fluid component quantitative meter according to claim 2, further comprising a function of displaying the accuracy grade of the measurement result based on the detection signal. (6) The body fluid component quantitative meter according to claim 2, further comprising a function of indicating that measurement is impossible based on a detection signal.