JPH03123863A - Immunoassay method and instrument - Google Patents

Abstract

PURPOSE:To obtain an antigen-antibody reaction weight by calculating the offset value at the reaction time based on reaction rate measurement data and making immunoassay based on an end point measurement method by using this offset value. CONSTITUTION:After a liquid to be tested is so injected as to come into contact with the reaction surface of an optical waveguide, the antigen-antibody reaction rate measurement data is obtd. by the rate measurement method. The offset value at the point of the time when the antigen-antibody reaction starts is calculated in accordance with this data. The measurement data at nearly the satd. point of time is obtd. by the end point measurement method. The true measurement data occurring in the antigen-antibody reaction is obtd. by calculating the difference between this measured data and the offset value.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an immunoassay method and an apparatus thereof, and more specifically, to evanescent waves generated by propagating excitation light while undergoing total internal reflection within a leading waveguide. The present invention relates to a method and apparatus for exciting a labeled fluorophore with a component and measuring the degree of immunity based on the intensity of fluorescence emitted from the labeled fluorophore.

<Prior art and problems to be solved by the invention> Conventionally, as a device for performing immunoassay by exciting a labeled fluorophore with an evanescent wave component, an optical cell for measurement and an optical cell for reference have been used. A double beam type device that corrects the measurement data obtained by the measurement optical cell using the measurement data obtained by the reference optical cell as an offset value, and the measurement optical cell are prepared. Before performing the antigen-antibody reaction, inject a buffer solution and measure the offset value, then replace the buffer solution with the test solution and perform the antigen-antibody reaction, and when the equilibrium is reached, measure the measured data. and an apparatus that performs correction based on an offset value.

In both devices, the offset value is obtained before any antigen-antibody reaction takes place, and the antigen-antibody reaction measurement data is corrected based on the offset value. It is expected that it will be possible to perform effective immunoassays.

However, in the former device, if the optical cell for measurement and the optical cell for reference do not have the same characteristics, there is no guarantee that measurement accuracy will improve even if correction is performed based on the offset value. Furthermore, since two optical cells are required, there is a problem in that a complicated optical system is required to obtain excitation light guided to each optical cell.

In addition, in the latter device, since it is necessary to replace the test solution with the buffer solution, there are problems in that the number of processing steps and the time required for processing increase, and the device for replacing the solution becomes complicated. If 100% of the solution is not replaced, the test solution will be diluted by the remaining buffer solution, resulting in a decrease in measurement accuracy. Furthermore, in practice, the starting point of the reaction and the sampling
There is no guarantee that the timing will match, and there is also a certain amount of time required for the diffusion of fluorescently labeled antibodies, etc. immediately after injection of the test solution, and the reaction curve will be S-shaped. There is a problem in that there is no guarantee that the offset value is an accurate offset value, and there is a high possibility that the measurement accuracy will be impaired.

Furthermore, because both devices use the so-called end-point measurement method, in which the measurement data at the point when the antigen-antibody reaction is almost at equilibrium is corrected using an offset value, it is possible to use the so-called end-point measurement method for a significantly long period of time, regardless of the degree of immunity. becomes necessary.

In addition, in order to eliminate the inconvenience of a long time required for measurement, antigen-antibody reaction rate measurement data after the reaction start time is obtained, and the degree of immunity is measured based on the maximum value of the antigen-antibody reaction rate measurement data. A rate measurement method has been proposed. According to this method, the time required for measurement can be significantly shortened, but if the degree of immunity is extremely low, the S/N ratio will decrease, resulting in insufficient measurement accuracy. There's a problem.

<Object of the invention> This invention was made in view of the above problems,
It is an object of the present invention to provide an immunoassay method and an apparatus for the same, which can improve measurement accuracy using an end point measurement method.

Another object of the present invention is to provide a novel immunoassay method and an apparatus for the same, in which a rate measurement method or an end point measurement method can be selected depending on the degree of immunity.

Means for Solving the Problems> In order to achieve the above object, the immunoassay method of the present invention obtains reaction rate measurement data based on a rate measurement method,
In this method, an offset value at the reaction time is calculated based on the obtained reaction rate measurement data, and the calculated offset value is used to perform an immunoassay based on an end point measurement method.

The immunoassay method of the second invention performs an immunoassay based on the rate measurement method to obtain reaction rate measurement data, and determines whether or not sufficient measurement accuracy is obtained, thereby obtaining a sufficient 1TllJ determination result. If it is determined that the reaction rate measurement data obtained by the rate measurement method is used as is, and if it is determined that sufficient measurement accuracy cannot be obtained, then the reaction rate measurement data obtained by the rate measurement method is used. In this method, an offset value at the reaction start time is calculated, and the offset value is used to use reaction measurement data based on the end point measurement method.

However, even if the regression interval is made sufficiently shorter than the reaction time constant and the offset value is calculated by performing linear regression up to the reaction start time based on the reaction rate measurement data obtained by the rate measurement method, good.

Alternatively, a method may be used in which it is determined that sufficient measurement accuracy cannot be obtained when the immunoassay result based on the rate measurement method is smaller than a predetermined threshold.

To achieve the above object, the immunoassay device of the present invention includes a rate measuring means for obtaining antigen-antibody reaction rate measurement data based on a rate measuring method, and an antigen-antibody reaction rate measurement data obtained by the rate measuring means. offset value calculation means for calculating an offset value by extrapolating the antigen-antibody reaction curve up to the reaction start time using the data; and a offset value calculation means for calculating an offset value by extrapolating the antigen-antibody reaction curve up to the reaction start time; It has an end point measuring means that calculates the difference between the data and the offset value and outputs it as antigen-antibody reaction measurement data.

The immunoassay device of the sixth invention includes a rate measuring means for obtaining antigen-antibody reaction rate measurement data based on a rate measurement method, and a measurement accuracy based on the antigen-antibody reaction rate measurement data obtained by the rate measuring means. The rate 1lPJ was obtained by the rate 1lPJ determination means on the condition that an output signal was supplied from the accuracy determination means for determining whether the measurement accuracy was sufficient and the output signal from the accuracy determination means for indicating that the measurement accuracy was determined to be insufficient. offset value calculation means for calculating an offset value by extrapolating the antigen-antibody reaction curve up to the reaction start time using the antigen-antibody reaction rate measurement data; an endpoint measurement means that calculates the difference between the obtained reaction measurement data and the offset value and outputs it as antitherapy-antibody reaction measurement data; and an antigen-antibody reaction measurement based on the output data from the rate measurement means. It has a conversion means for obtaining data, and a selection means for selecting output data from the conversion means or output data from the endpoint measurement means based on the output signal from the accuracy determination means.

In the above immune Δ-1 determination method, the test solution is injected so that it comes into contact with the reaction surface of the leading waveguide, and then the antigen-antibody reaction rate measurement data is obtained by the rate measurement method.
An offset value at the start of the antigen-antibody reaction can be calculated based on the antibody reaction rate measurement data. Therefore, after that, by the end point measurement method,
By obtaining measurement data at the time of saturation and calculating the difference from the offset value, true measurement data resulting from the antigen-antibody reaction can be obtained.

In the immunoassay method of the second invention, the test solution is injected so as to be in contact with the reaction surface of the leading waveguide, and then the antigen-antibody reaction rate measurement data is obtained by the plasma measurement method, and based on this measurement data. It can be determined whether sufficient measurement results can be obtained using the rate measurement method. Therefore, when it is determined that sufficient measurement accuracy can be obtained, measurement data indicating the amount of antigen-antibody reaction can be obtained based on the obtained antigen-antibody reaction rate data. On the other hand, if it is determined that sufficient measurement accuracy cannot be obtained, it is possible to calculate the offset value at the start of the antigen-antibody reaction based on the antigen-antibody reaction rate measurement data obtained by the rate measurement method. can. Therefore, after that, the end
By the point measurement method, measurement data is obtained at the time of saturation, and by calculating the difference from the offset value, true measurement data resulting from the antigen-antibody reaction can be obtained.

Then, if the regression interval is made sufficiently shorter than the reaction time constant, and the offset value is calculated by performing linear regression up to the reaction start time based on the reaction rate measurement data obtained by the rate measurement method, can be adapted to real-time processing by shortening the calculation time required.

Further, if the method determines that sufficient measurement accuracy cannot be obtained when the immunoassay result based on the rate measurement method is smaller than a predetermined threshold value, the determination process can be simplified.

With the immunoassay device having the above configuration, after the test liquid is injected so as to be in contact with the reaction surface of the leading waveguide, antigen-antibody reaction rate measurement data is obtained by the rate measuring means, so this antigen-antibody reaction rate measurement data is obtained. Based on this, the offset value calculation means can calculate the offset value at the start of the antigen-antibody reaction. Therefore, after that,
The end point measuring means obtains measurement data at the point of saturation, and by calculating the difference from the offset value, true measurement data resulting from the antigen-antibody reaction can be obtained.

In the immunoassay device of the sixth invention, after the test liquid is injected so as to be in contact with the reaction surface of the leading waveguide, the antigen-antibody reaction rate measurement data is obtained by the rate measuring means, so the accuracy is based on this measurement data. The determining means can determine whether or not sufficient measurement results can be obtained using the rate measurement method.

If the accuracy determination means determines that sufficient measurement accuracy is obtained, the conversion means and selection means obtain measurement data indicating the amount of antigen-antibody reaction based on the obtained antigen-antibody reaction rate data. be able to. vice versa,
If it is determined that sufficient measurement accuracy cannot be obtained, the offset value at the start of the antigen-antibody reaction is calculated by the offset value calculation means based on the antigen-antibody reaction rate measurement data obtained by the rate measurement means. be able to. Therefore, after that, the end point measurement means obtains measurement data at the point of saturation.
By calculating the difference from the offset value, true measurement data resulting from the antigen-antibody reaction can be obtained.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 7 is a perspective view showing a schematic configuration of an optical measurement device used in the immunoassay method of the present invention, in which a slab-type leading waveform is integrally formed with prism portions (21a) as light input/output portions at both ends. A casing (22) is provided to surround (21). An antibody (23) is fixed in advance on the surface of the slab-type leading waveguide (21). Further, a space surrounded by the casing (22) is a reaction tank (22a).

FIG. 1 is a flowchart showing an embodiment of the immunoassay method of the present invention, in which the introduction of excitation light to the slab-type leading waveguide (21) is started in step (2), and in step (2)
, a measurement based on a rate measurement method is started at a preset sampling time. Then, in step (2), the antigen-antibody reaction proceeds by diluting the test solution containing the antigen (23a) and replacing the buffer in the reaction tank (22a) with a solution containing the fluorescently labeled antibody (23b). Therefore, a signal corresponding to the reaction rate can be obtained. This signal is determined based on the tangent slope of the antigen-antibody reaction curve, so
In step (2), by extrapolating the obtained signal, the signal level at the start of the reaction, that is, the offset value can be calculated. Therefore, after that, in step (2), measurement based on the end point measurement method is started, in step (2), wait until the level of the measurement signal hardly changes, and in step (2), the measurement signal whose level has hardly changed is measured. The difference between the offset value and the offset value is obtained, and in step (2), the amount of antigen-antibody reaction can be obtained based on the difference.

FIG. 2 is a diagram showing the temporal change in the obtained measurement signal, and even though only the buffer solution is initially contained in the reaction tank (22a), the light emitted from the slab-type leading waveguide (21) itself A measurement signal of a certain level (offset value due to the slab-type leading waveguide) can be obtained by light, Raman scattering, etc. (
(See region R1 in FIG. 2). Initially, when the buffer solution was replaced with a test solution mixed with a fluorescently labeled antibody, no antigen-antibody reaction occurred, but the reaction occurred due to the fluorescently labeled antibody present near the reaction surface of the slab-type leading waveguide (21). The measurement signal suddenly rises by the offset value (see point R2 in Figure 2).
After that, the level of the measurement signal gradually increases at a rate determined based on the amount of antigen present in the test solution (see region R3 in Figure 2), and after a certain amount of time, the level of the measurement signal becomes almost zero. An unchanging equilibrium state is reached (see region R4 in FIG. 2).

Therefore, measurements are performed based on the rate measurement method at the beginning of the antigen-antibody reaction, and based on this measurement data, an offset value at the beginning of the antigen-antibody reaction is obtained by a linear regression method, a nonlinear regression method, a piecewise interpolation method, etc. be able to. To explain in more detail, the signal intensity 5(t) (see FIG. 3) at the beginning of the immune reaction can be expressed as a first approximation using an exponential function as follows.

S (t)-a+b cxp(-t/r) (however, a
, b is a constant, and τ is a reaction time constant that depends on the activity of the reaction and can take values from tens of seconds to hundreds of seconds) In addition to the above exponential function, S (t) −a+b exp(−t/r ) +c e
Approximate expression using a function such as xp(-t/τ') is also possible. However, performing regression calculations using these approximate expressions not only takes a large amount of time to calculate due to non-linearity, but also makes it difficult to predict the time required for convergence, so it cannot be applied to real-time processing. do not have. As a result of intensive research taking these points into consideration, we found that if the regression interval T satisfies a specific relationship with the reaction time constant τ, it is possible to suppress the decrease in accuracy of the offset value obtained by linear regression. Ta. That is, T
If <<[tau], linear regression of S(t)-a t+b is possible, and if T~[tau], regression using a linear polynomial such as parabolic regression of s<t>-aJt is possible. Linear regression is the most preferable in terms of calculation stability, elegance, etc., but the regression interval may become significantly shorter, resulting in lower accuracy.

Therefore, it seems to be appropriate to lengthen the regression interval T when the signal is low and the decrease in accuracy becomes noticeable. This kind of treatment is
This method is effective when the main cause of decreased accuracy at low signal times is not a misfit between the data and the regression curve, but random noise contained in the data. In addition, the immune reaction is not strictly a first-order reaction, and the apparent reaction time constant when approximating the first-order reaction tends to be long when the signal is low.
From this point as well, it can be seen that it is effective to adaptively change the rotation section T. The method of determining the interval in this case is as follows: ■ A method of first performing regression in a short regression interval, and extending the regression interval to a predetermined length if the coefficient (slope) in that regression interval is less than a predetermined threshold. , ■ A method of extending the regression interval based on the magnitude of the slope in the first regression interval in accordance with a predetermined conversion table or formula, ■ A method in which the sum of squared residuals of the regression or its average exceeds a predetermined value. Examples include methods for extending the regression interval to

Furthermore, since the level of the measurement signal is not saturated while performing measurements based on the rate measurement method, it is only necessary to perform measurements based on the end point method after obtaining the offset value as described above. By calculating the difference between the saturated measurement signal and the offset value, a signal corresponding to the amount of antigen-antibody reaction can be obtained.

Furthermore, instead of storing a buffer solution in the reaction tank (22a) in advance, it is also possible to keep the reaction surface of the slab type optical waveguide (21) in a dry state, and in this case, the initial measurement signal is Although the level is high as shown by the broken line in Figure 2, the measurement signal changes in the same way as above after mixing the fluorescently labeled antibody and injecting the test solution, so it is also a highly accurate end point. AllJ constant results can be obtained. In this case, the apparatus and operation can be simplified by eliminating the need for liquid replacement.

<Example 2> FIG. 4 is a flowchart showing another example of the immunoassay method, in which a slab-type leading waveguide (21
), and in step (2), a1 constant is started based on the rate measurement method at a preset sampling time.

Then, in step (2), the antigen-antibody reaction proceeds by diluting the test solution containing the antigen (23a) and replacing the buffer in the reaction tank (22a) with a solution containing the fluorescently labeled antibody (23b). Therefore, a signal corresponding to the reaction rate can be obtained. Therefore, in step (2), it is determined whether or not sufficient measurement accuracy can be obtained by the rate measurement method based on the signal or the maximum value of the signal at a predetermined timing. If it is determined in this step (■) that sufficient measurement accuracy can be obtained using the rate a91 standard method, in step (2),
An immunoassay result is obtained by performing a predetermined calculation based on the maximum value of the obtained signal.

On the other hand, if it is determined in step (2) that sufficient measurement accuracy cannot be obtained with the rate measurement method, in step (2), the level of the signal at the start of the reaction, i.e., is determined by extrapolating the obtained measurement signal. Offset values can be calculated. Therefore, after that, in step (2), wait until the level of the measurement signal hardly changes, then in step (2) obtain the difference between the measurement signal whose level has hardly changed and the offset value, and in step (2), based on the difference. By performing predetermined calculations, the antigen-
The amount of antibody reaction can be obtained.

Therefore, in the case of this example, if the degree of immune reaction is high, it is possible to perform a highly accurate immunoassay in a short time using the rate measurement method, and if the degree of immune reaction is low, it is possible to perform an immunoassay with high accuracy based on the rate measurement method. By extrapolating the reaction equation using the measured data obtained, an accurate offset value at the time of reaction initiation can be obtained, and this offset value can be used to perform highly accurate immunoassays using the end point measurement method. Note that the accuracy of the offset value obtained by extrapolation will be higher if the slope of the response curve is gentle, and lower if it is steep; however, measurements based on the end point measurement method are performed using the offset value. This is true only when the slope of the reaction curve is gentle, so there is no problem at all.

<Embodiment 3> FIG. 5 is a block diagram showing an embodiment of the immunoassay device of the present invention, which includes a detector that receives fluorescent light that changes depending on the amount of antigen-antibody reaction and converts it into an electrical signal. (1), a sampling circuit (2) that samples the signal output from the detector (1), a regression interval setting section (3) that sets the regression interval T, and a sampled signal and the set regression interval. a slope calculation unit (4) that calculates the slope of a straight line in a set regression interval T based on T; and a comparison unit (5) that determines whether the calculated slope is less than or equal to a preset threshold. , an offset value calculation unit (6) that calculates an offset value by performing linear regression based on the sampling signal within the regression interval T, and an equilibrium determination unit (7) that determines whether the sampling signal is balanced. , a reaction amount calculation unit (8) that calculates the antigen-antibody reaction amount based on the sampling signal at equilibrium and the calculated offset value, and a comparison unit (5) output a determination result indicating that the reaction amount is below the threshold value. Under this condition, the regression interval T to be set by the regression interval setting unit (3) is changed to a previously set regression interval, and the offset value calculation unit (6) is operated based on the changed regression interval. It has a control section (9) for controlling.

The operation of the immune system 71p] configured as described above is as follows.

First, the regression interval setting section (3) sets a regression interval T that is sufficiently shorter than the reaction time constant τ. Then, the signals sampled by the sampling circuit (2) are sequentially taken in, and the slope of the linear regression equation is calculated by the slope calculation unit (4) based on the sampling signals in the range of the regression interval T, and the calculated slope is set in advance. The comparison unit (5) determines whether or not it is less than or equal to the set threshold value.

If it is determined that the calculated gradient is larger than the threshold value, the offset value calculation unit (6) performs linear regression based on the sampling signal within the regression interval T to calculate the offset value. After that, the equilibrium discriminator (7)
It is possible to determine whether the sampling signal is balanced or not, and to calculate the antigen-antibody reaction amount by the reaction amount calculation unit (8) based on the sampling signal at the time when it is determined that the sampling signal is balanced and the calculated offset value. can.

Conversely, if it is determined that the calculated slope is less than the threshold, the control unit (9) changes the regression interval to a preset long regression interval, and offsets the regression interval based on the changed regression interval. The antigen-antibody reaction amount can be calculated by performing a value calculation operation, an equilibrium determination operation, and a reaction amount calculation operation.

That is, compared to the conventional apparatus, the offset value can be calculated more accurately, and the calculated offset value can be used to perform highly accurate immune ΔIII determination by the end point measurement method.

<Embodiment 4> FIG. 6 is a block diagram showing another embodiment of the immunoassay device of the present invention. The difference from the embodiment of FIG. 5 is that the slope of the reaction curve is determined based on the sampled signal. Maximum value extraction unit 00) that calculates and extracts the maximum value of the gradient.
and a reaction amount calculation unit (11) that calculates the antigen-antibody reaction amount based on the maximum slope, and the slope of the linear regression equation when the regression interval is changed to a preset length. is below a predetermined threshold (the control unit (9) operates the comparison unit (5), and based on the determination result in this case, one of the reaction amount calculation units (8) ) (I!, ) The only difference is that a selection section (12) for selecting the calculated amount from (I!, ) is further provided.

Therefore, in the case of this example, if the slope of the linear regression equation is greater than the threshold in both the regression interval sufficiently shorter than the reaction time constant and the preset long regression interval, the maximum value is extracted. The selection section (12) may select the antigen-antibody reaction amount calculated by the reaction amount calculation section (11) based on the maximum gradient extracted by the section (10), and there is no need to wait until the sampling signal is balanced. Since there is no need for immunoassay, the time required for immunoassay can be shortened. Furthermore, the accuracy of immunoassay can be made sufficiently high.

On the other hand, if the slope of the linear regression equation is below the threshold value in any regression interval, highly accurate immune in++ determination can be achieved based on the end point measurement method as in the above embodiment.

In summary, immunoassays using the end point assay can be performed only when sufficient measurement accuracy cannot be obtained using the rate assay method, and the increase in time required when performing immunoassays on a large number of test solutions can be avoided. It is possible to shorten the time and achieve immunoassay with sufficient accuracy.

It should be noted that the present invention is not limited to the above-mentioned embodiments. For example, the regression interval set by the regression interval setting unit (3) is made to correspond to the magnitude of the slope in the initial regression interval, and a conversion table or the like is created. The regression interval can be configured to be selected based on the regression interval, or can be configured to extend the regression interval until the regression residual sum of squares or its mean is greater than or equal to a predetermined value; Various changes can be made to the system without changing the gist of the invention.

<Effects of the Invention> As described above, the first invention makes it possible to accurately calculate the offset value, which conventionally tends to be inaccurate, based on the reaction rate measurement data obtained by the rate measurement method. This has the unique effect of increasing the measurement accuracy by the end point measurement method.

In the second invention, when sufficient accuracy can be obtained by the rate measurement method, measurement is performed using the rate all + standard method, and in other cases, an accurate offset value is obtained based on the measurement data obtained by the rate measurement method. , it has the unique effect of increasing the measurement accuracy by the end point measurement method.

The third invention has the unique effect of being able to shorten the time required for computation and adapt to real-time processing.

The fourth invention can simplify the process of determining whether the liquid is a rate measurement method or an end point measurement method.

The fifth invention is that the offset value, which conventionally tends to be inaccurate, can be accurately calculated based on the reaction rate ΔPj constant data obtained by the rate measurement method, and the measurement accuracy by the end point measurement method can be improved. It has the unique effect of increasing the

In the sixth invention, if sufficient accuracy can be obtained by the rate measurement method, measurement is performed by the rate measurement method, and in other cases, an accurate offset value is obtained based on the measurement data obtained by the rate measurement method. , it has the unique effect of being able to improve the i+p1 determination accuracy by the end point measurement method.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing an embodiment of the immunoassay method of the present invention, FIG. 2 is a diagram showing temporal changes in the obtained measurement signal, FIG. 3 is a diagram showing details of signal changes at the initial stage of the reaction, and FIG. FIG. 4 is a flowchart showing another embodiment of the immunoassay method of the present invention, FIG. 5 is a block diagram showing an embodiment of the immunoassay device of the present invention, and FIG. 6 is a flowchart showing another embodiment of the immunoassay device of the present invention. A block diagram showing an embodiment. FIG. 7 is a perspective view showing a schematic configuration of an optical measuring device used for immunoassay. (11)...Reaction amount calculation unit as a conversion means, (12
)...Selection section

Claims (1)

[Claims] 1. Obtaining reaction rate measurement data based on a rate measurement method,
An immunoassay method characterized by calculating an offset value at a reaction time based on the obtained measurement data, and performing an immunoassay based on an end point measurement method using the calculated offset value. 2. Perform immunoassay based on the rate measurement method to obtain reaction rate measurement data, determine whether or not sufficient measurement accuracy can be obtained, and if it is determined that sufficient measurement results can be obtained, Using the reaction rate measurement data as is, conversely,
If it is determined that sufficient measurement accuracy cannot be obtained, an offset value at the reaction start time is calculated based on the reaction rate measurement data obtained by the rate measurement method, and the offset value is used to perform the end point measurement method. An immunoassay method characterized by using reaction measurement data based on. 3. Make the regression interval sufficiently shorter than the reaction time constant,
The immunoassay method according to claim 1 or 2, wherein the offset value is calculated by performing linear regression up to the reaction start time based on the reaction rate measurement data obtained by the rate measurement method. 4. The immunoassay method according to claim 2, wherein if the immunoassay result based on the rate measurement method is smaller than a predetermined threshold value, it is determined that sufficient measurement accuracy cannot be obtained. 5. Using rate measurement means (2) (4) to obtain antigen-antibody reaction rate measurement data based on the rate measurement method and antigen-antibody reaction rate measurement data obtained by rate measurement means (2) (4). offset value calculation means (6) for calculating an offset value by extrapolating the antigen-antibody reaction curve up to the reaction start time, and obtaining reaction measurement data at the time when the antigen-antibody reaction is almost in equilibrium, An immunoassay device characterized by comprising endpoint measuring means (7) and (8) for calculating the difference between the data and the offset value and outputting the calculated difference as antigen-antibody reaction measurement data. 6. Rate measurement means (2) (4) (10) for obtaining antigen-antibody reaction rate measurement data based on the rate measurement method;
4) Accuracy determining means (5) for determining whether the measurement accuracy is sufficient based on the antigen-antibody reaction rate measurement data obtained in (10), and a means for determining whether the measurement accuracy is insufficient. The antigen-antibody reaction rate measurement data obtained by the rate measuring means (2) and (4) are used to determine the antigen-antibody reaction rate until the reaction start time, on the condition that the output signal from the accuracy determining means (5) shown in FIG. Offset value calculation means (6) for calculating an offset value by extrapolating the reaction curve;
Endpoint measurement means (7) that obtains antigen-antibody reaction measurement data when the antibody reaction is almost in equilibrium, calculates the difference between the obtained reaction measurement data and the offset value, and outputs the result as antigen-antibody reaction measurement data ( 8), a converting means (11) for obtaining antigen-antibody reaction measurement data based on the output data from the rate measuring means, and an output from the converting means (11) based on the output signal from the accuracy determining means (5). An immunoassay device characterized in that it has a selection means (12) for selecting data or output data from the endpoint measurement means (8).