JP2934653B2 - Automatic analyzer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic analyzer for measuring a change in absorbance of a sample, and more particularly to a technique for improving the reliability of an analysis result by determining a detection limit. .

[Technological background]

In clinical biochemical tests, the processing speed of a sample has been remarkably improved by the spread of a reaction rate measuring device utilizing a change in absorbance of a sample, that is, an automatic analyzer.

However, the rate analysis, which is one of the analysis methods employed in such an automatic analyzer, is intended to reduce the rate of the main reaction involving the analyte in a steady state (there is almost no side reaction, and the substrate and other reactants are sufficient). The characteristic feature is that accurate measurement results can be obtained only when measurement is performed with the main reaction remaining at a constant rate.

FIG. 4 shows the change in absorbance in the most common two-reagent rate method. At time t ₀ , the first reagent (excluding some substrates and consisting of a reactant such as NADH or a buffer) was used. When added, it promotes enzyme activity and removes coexisting substances.
Advances the primary reaction, the absorbance decreases from A _0. At time t _1, after removal of the errors associated with the primary reaction, the main reaction when the addition of the second reagent (consisting of a substrate which is removed in the first reagent) is consumed NADH proceeds, the absorbance decreases again changes I do.

In such absorbance change, the time t ₂ ~t between ₅ corresponds to the steady state, the absorbance is also linearly varying region.
In the rate analysis, for a certain period of time in this linear region, for example, t _{3 to} t ₄
It is an indispensable condition that correct measurement is performed between them.

However, when the activity of substance to be measured is high concentration (shown in FIG. 4 in dashed lines) after the second reagent addition, rapid main reaction proceeds, for example, already NADH at the time of t ₃ Since the reaction is stopped (plateau state) due to the shortage, the change in absorbance is small, and therefore, there is a risk that an abnormal sample with high activity is erroneously measured as a normal sample with low activity.

(Prior art)

By the way, conventionally, as a means for preventing such an erroneous measurement, a limit absorbance corresponding to an interfering component (hemoglobin, bilirubin, etc.) is set for each sample, and this is compared with the final absorbance of each sample. An analysis method for determining whether or not the analysis was performed in a state is described in, for example, Japanese Patent Application Laid-Open No. 56-1089.
As shown in Japanese Patent Publication No. 41, it is publicly known.

FIG. 5 shows the absorption spectra of ideal serum containing no interfering component, serum containing strong emulsifying bi-hemolysis, and severe jaundice, which are the interfering components, as indicated by reference numerals 1, 2, 3, and 4, respectively.
To absorbance A ₁ of the ideal serum at a measurement wavelength of 340 nm, milk Pi, hemolysis the absorbance of sera containing jaundice A ₁ + alpha _L, A ₁ + alpha
_{Since H} and A ₁ + α _I are high, in this prior art, the α value is obtained for each sample, and the limit absorbance at which the reaction curve becomes a plateau is set.

 This α value is given by the following equation.

α = k ₁・ a _2-1 + k ₂ (a _4-3 −c ₁・ a _2-1 ) + k ₃ [a _6-5 −c ₂・ a _2-1 −c ₃ (a _4-3 −c ₁・ a _2-1 )) = k ₁・ a _2-1 + k ₂ (a _4-3 −c ₁・ a _2-1 ) + k ₃ (a _6-5 −c ₂・ a _2-1 −c ₃・ A _4-3 ) where α _L = k ₁・ a _2-1 α _H = k ₂ (a _4-3 −c ₁・ a _2-1 ) α _I = k ₃ (a _6-5 −c ′) _{2 · a 2-1 -c 3 · a} 4-3) c 2 = c 2 -c 1 · c 3 a 2-1; 2 two wavelengths lambda ₁ in the visible range, lambda ₂ of absorbance difference (e.g., lambda ₁ = 700 nm, λ ₂ = 660 nm) a _4-3 ; similarly, λ ₃ −λ ₄ (eg, λ ₃ = 600 nm, λ ₄ = 570 nm) a _6-5 ; similarly, λ ₅ −λ ₆ (eg, λ ₅ = 505 nm, λ ₆ = 480 nm) k ₁ , k ₂ , k ₃ , c ₁ , c ₂ , c ₃ ; experimental values obtained by analyzing the visible spectrum of actual samples such as hemoglobin samples and bilirubin samples , for example, when determined by the GOT determination _{reagent, k 1 = 9.25, k 2} = 2.47, k 3 = 0.51 c 1 = 0.83, c 2 = 1.42, c 3 = 0.10 Then, the conventional apparatus In other words, the final absorbance at the time when the measurement is actually completed is compared with the limit absorbance obtained in this way, and when the final absorbance exceeds the limit absorbance (in the case of a decrease reaction, Then, at the time of the above), it was configured to notify the abnormality of the inspection result by adding a comment to the result value.

[Problems to be solved by the invention]

However, in such an automatic analyzer using the conventional rate analysis method, when the value of the limit absorbance changes due to a change in the composition of the reagent or the like, the final absorbance does not exceed the limit value. Even if a sudden reaction occurs and the state changes to a plateau state, this cannot be detected and the data is very low (or high) without any comment
A value may occur (see FIG. 6). In addition, there is a tendency that the limit absorbance is set very close in order to extend the measurement range as much as possible. In this case, there is a problem that the final absorbance does not fall below the limit value and the same problem occurs.

The present invention has been made in view of the above situation, and has as its object to provide a reaction vessel that moves intermittently at a constant speed; and a pipette that adds a specimen and a reagent to the reaction vessel. A photometer that splits the luminous flux transmitted through the reaction vessel containing the sample and the reagent added by the pipette, and converts it into a voltage; and converts the converted voltage output from the photometer into a pulse signal and outputs it. AD
A converter; an absorbance accumulator for receiving a pulse signal from the AD converter and accumulating a change in the absorbance of the transmitted light beam based on the pulse signal; and receiving an output of the absorbance accumulator to determine an absorbance at a spectral wavelength to a predetermined value. Create a reaction curve by plotting at the timing, smoothing the absorbance,
A microprocessor that determines a steady-state reaction region of the reaction curve by setting a threshold based on the maximum differential absolute value; and a peripheral device that outputs a determination result by the microprocessor in a predetermined format. When the determination result exceeds a threshold, a signal indicating that the reaction is not a reaction in a steady state is output to the absorbance integrating device, and drive control is performed so as to automatically stop a series of control operations. It is an object of the present invention to provide an automatic analyzer characterized by the following.

[Means for solving the problem]

In order to achieve the above object, an automatic analyzer according to the present invention includes a reaction container that moves intermittently at a constant speed; a pipette for adding a sample and a reagent to the reaction container;
A photometer that splits the luminous flux transmitted through the reaction vessel containing the sample and the reagent added by the pipette and then converts it into a voltage; and converts the converted voltage output from the photometer into a pulse signal and outputs it. An AD converter; an absorbance integrating device that receives a pulse signal from the AD converter and integrates a change in the absorbance of the transmitted light flux based on the pulse signal; and receives an output of the absorbance integrater to determine the absorbance at a spectral wavelength. A microprocessor device which plots a reaction curve at the timing of, prepares a response curve, smoothes the absorbance, sets a threshold value based on the maximum absolute differential value, and determines a steady-state reaction region of the reaction curve; A peripheral device that outputs a result of the determination by the processor device in a predetermined format; and when the result of the determination exceeds a threshold value, the device returns to a steady state. A signal indicating that the reaction is not a reaction to be performed is output to the absorbance integrating device, and drive control is performed to automatically stop a series of control operations.

〔Example〕

Hereinafter, the present invention will be described in detail based on an embodiment shown in the accompanying drawings.

FIG. 1 shows an automatic analyzer according to this embodiment, in which reference numeral 10 denotes a transparent reaction vessel that moves intermittently at a constant speed, and 11 denotes a sample and a first reagent to the reaction vessel 10. A pipette to add, 12 a pipette to add a second reagent,
13 is a light source, 14 is a photometer that spectrally converts light transmitted through the reaction vessel 10 into a plurality of wavelengths and converts the voltage, 15 is an AD converter, 16 is an absorbance integrating device that integrates an absorbance change based on an input voltage value, 17 Is a concentration conversion device for obtaining the concentration of the sample, 18 is a CRT for displaying an image of the measurement result, 19 is a printer device for printing out the measurement result, and a microprocessor device denoted by reference numeral 20 is an input voltage or absorbance integration device 16. A limit absorbance determination circuit that outputs to the absorbance integrating device 16 when the absolute value of the derivative of the reaction curve based on the output exceeds a preset threshold value
It has 21.

Next, the operation of the present automatic analyzer having the above configuration will be described.

The luminous flux transmitted through the reaction vessel 10 is spectrally separated by a photometer 14 and then subjected to voltage conversion, and a pulse signal having passed through an AD converter 15 is input to an absorbance integrating device 16.

The absorbance integrator 16 plots the absorbance value of the spectral wavelength at a predetermined timing based on the input pulse signal to create a reaction curve. Here, a limit absorbance determination circuit 21 for determining a steady-state reaction region is used. Works as follows.

Now, when the reaction curve is in a state as shown in FIG. 2A, the limiting absorbance determination circuit 21 determines the steady-state reaction region (linear region) by taking the differential value of the curve in principle (second region).
Figure b). However, since the actual reaction curve has data variations, the absorbance is smoothed, and then a differential value is obtained and determined (FIG. 2c). In this case, the absorbance value of each point as A _i, A value after the smoothing and AA _i, performs smoothing using weighted moving average method as shown in the following equation. That is, _{AA i = A i-3 +} 2 × A i-2 + 3 × A i-1 + 4 × A i + 3 × A i + 1 + 2 × A i + 2 + A i + 3.

When the maximum value of the differential absolute value after such smoothing processing is Dmax, the limit absorbance (threshold for plateau determination) T in the automatic analyzer is defined as, for example, T = −2 / 3 × Dmax, This is set in the limit absorbance determination circuit 21 in advance.

In the case of a decrease reaction, the differential value calculated by the absorbance integrating device 16 is changed to the threshold value T from one point before the threshold value T is exceeded.
The region between the smaller points is determined to be a steady-state reaction, and the other region is determined to be likely not to be a steady-state reaction, and the limit absorbance determining circuit 21 outputs a determination signal to the absorbance integrating device 16. The post-processing based on the determination signal is as follows.

For example, first, a predetermined mark (L mark for a decreasing reaction, H mark for an increasing reaction, etc.) indicating that the measured absorbance value has exceeded the limit absorbance value together with the measurement data.
Is printed out, whereby it is possible to reliably know that the sample has a high concentration, and to take subsequent measures such as re-measurement and reagent deterioration check.

Second, when the judgment signal is output, the time course of the response curve is stopped thereafter, the fact is displayed on the CRT 18 or the like, and the measurement result of only the steady region is printed out. As a result, it is possible to obtain data with extremely high reliability as compared with the conventional measurement result up to the final absorbance value.

In addition, in the case of the conventional apparatus, the case where the progress of the main reaction is rapid and the steady area is narrow or the slope is steep and the steady area cannot be calculated has occurred. If a threshold is set based on (the part where the slope of the straight line is the maximum) and the time course is set to be exceeded, a straight-line area can be reliably set by ordinary least squares calculation Becomes The slope calculation by the least squares method is as follows (see FIG. 3).

Rate value However, n = ml + 1 [Effect of the Invention] As described above, according to the automatic analyzer according to the present invention, the differential absolute value of the reaction curve exceeds the preset threshold based on the maximum absolute value. At this time, a signal indicating that the reaction is not a steady-state reaction was output to the absorbance integrating device, and a series of control operations was automatically stopped. Even if the process is shifted to the reaction stopped state, an excellent effect that the processing state can be clearly determined by reliably capturing only the reaction region in the steady state, and the reliability of the rate analysis including the high-concentration sample is further improved is achieved.

[Brief description of the drawings]

FIG. 1 is a system block diagram showing an automatic analyzer according to an embodiment of the present invention, FIG. 2 is a graph showing an example of processing by the automatic analyzer, and FIG. 3 is a graph showing an inclination of absorbance. , FIG. 4 is a graph showing a general absorbance change curve, FIG. 5 is a graph illustrating the relationship between an interference component and absorbance, and FIG. 6 is a relationship between a reaction curve of a high concentration sample and a conventional limit absorbance. FIG. [Explanation of symbols] 14: photometer, 16: absorbance integrating device 20: microprocessor device 21: limit absorbance determination circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/75 G01N 21/59 G01N 35/00 JICST

Claims (1)

(57) [Claims] 1. A reaction vessel which moves intermittently at a constant speed; a pipette for adding a specimen and a reagent to the reaction vessel; and a permeation through the reaction vessel containing the specimen and the reagent added by the pipette. A photometer that converts the converted luminous flux into a voltage and converts the converted voltage into a voltage; an AD converter that converts the converted voltage output from the photometer into a pulse signal and outputs the pulse signal;
An absorbance integrating device that receives a pulse signal from the AD converter and integrates the change in the absorbance of the transmitted light flux based on the pulse signal; and receives the output of the absorbance integrater and plots the absorbance of the spectral wavelength at a predetermined timing. A microprocessor device for creating a reaction curve, smoothing the absorbance, setting a threshold based on the maximum differential absolute value, and determining a steady-state reaction region of the reaction curve; and a determination result by the microprocessor device And a peripheral device that outputs a signal in a predetermined format. When the determination result exceeds a threshold value, a signal indicating that the reaction is not a reaction in a steady state is output to the absorbance integrating device, and a series of control operations are performed. An automatic analyzer configured to perform drive control so as to automatically stop the operation.