JP2636439B2 - Immunoassay method and device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an immunoassay method and an apparatus therefor, and more specifically, an evanescent wave generated by propagating excitation light while totally reflecting inside an optical waveguide. The present invention relates to a method and an apparatus for exciting a labeled phosphor with a component and measuring the presence or absence of immunity and the degree of immunity based on the intensity of the fluorescence emitted from the labeled phosphor.

<Prior Art and Problems to be Solved by the Invention> Conventionally, an optical cell for measurement and an optical cell for reference have been used as an apparatus for performing an immunoassay by exciting a labeled phosphor with an evanescent wave component. Using, a double-beam system for correcting the measurement data obtained by the optical cell for measurement as an offset value of the measurement data obtained by the optical cell for reference, and only the optical cell for measurement are prepared, Before the antigen-antibody reaction is performed, a buffer solution or the like is injected to measure the offset value, and then the buffer solution is replaced with a test solution to perform the antigen-antibody reaction. And a device for performing a correction based on an offset value.

In any of the apparatuses, an offset value is obtained in a state where no antigen-antibody reaction is performed, and correction based on the offset value is performed on the antigen-antibody reaction measurement data. It is expected that immunoassays can be performed.

However, in the former device, if the characteristics of the optical cell for measurement and the optical cell for reference are not uniform, there is no guarantee that the measurement accuracy will be improved even if the correction based on the offset value is performed. In addition, there is a problem that a complicated optical system is required to obtain the excitation light guided to each optical cell as two optical cells are required.

Further, in the latter device, since the replacement of the test solution with the buffer solution becomes essential, there is a problem that the number of processing steps and the required processing time increase, and the device for replacing the solution becomes complicated. If the replacement of the solution is not performed 100%, the test solution will be diluted by the remaining buffer solution, and the measurement accuracy will be reduced. Furthermore, in practice, the reaction start time and sampling
There is no guarantee that the timing coincides, and some time is required immediately after injection of the test solution for diffusion of the fluorescently labeled antibody, etc., and the reaction curve becomes S-shaped. Is not guaranteed to be an accurate offset value, and there is a high possibility that the measurement accuracy is rather deteriorated.

Furthermore, in any of the apparatuses, since the so-called endpoint measurement method is employed, in which the measurement data at the time when the antigen-antibody reaction is substantially equilibrated is offset, the so-called endpoint measurement method is employed. Is required.

Further, in order to solve the problem that the measurement time is long, 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. Rate measurement methods have been proposed. According to this method, the time required for measurement can be significantly shortened, but when the degree of immunity is extremely low, the S / N ratio decreases, and as a result, sufficient measurement accuracy cannot be obtained. There's a problem.

<Object of the Invention> The present invention has been made in view of the above problems, and an object of the present invention is to provide an immunoassay method and an apparatus thereof capable of improving the measurement accuracy by an end point measurement method.

Another object of the present invention is to provide a novel immunoassay method and an apparatus therefor which can select a rate measurement method or an end point measurement method according to 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, and performs a reaction based on the obtained reaction rate measurement data. In the method of calculating the offset value at the start time and performing an immunoassay based on the end point measurement method using the calculated offset value, the regression interval is set sufficiently shorter than the reaction time constant, and the rate measurement method is used. In this method, an offset value is calculated by performing a linear regression until the reaction start time based on the obtained reaction rate measurement data.

In the immunoassay method of the second invention, an immunoassay based on a rate measurement method is performed to obtain reaction rate measurement data, and it is determined whether or not sufficient measurement accuracy is obtained. If it is determined, the obtained reaction rate measurement data is used as it is, and if it is determined that sufficient measurement accuracy is not obtained, based on the reaction rate measurement data obtained by the rate measurement method, In this method, an offset value at a reaction start time is calculated, and reaction measurement data based on an end point measurement method is used using the offset value.

However, even if the regression interval is set sufficiently shorter than the reaction time constant, an offset value is calculated by performing a linear regression until 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, when the result of the immunoassay based on the rate measurement method is smaller than a predetermined threshold, sufficient measurement accuracy cannot be obtained.

In order to achieve the above object, an immunoassay apparatus of the present invention comprises a rate measuring means for obtaining antigen-antibody reaction rate measurement data based on a rate measurement method, and an antigen-antibody reaction rate measurement obtained by the rate measurement means. On the condition that an output signal is supplied from an accuracy discriminating means for discriminating whether or not the measurement accuracy is sufficient based on the data and an accuracy discriminating means indicating that the measurement accuracy is not sufficient, Offset value calculation means for calculating an offset value by extrapolating an antigen-antibody reaction curve until the reaction start time using the antigen-antibody reaction rate measurement data obtained by the measurement means, and at the time when the antigen-antibody reaction is substantially equilibrated. Obtain reaction measurement data,
Endpoint measurement means for calculating the difference between the obtained reaction measurement data and the offset value and outputting it as antigen-antibody reaction measurement data, and conversion for obtaining antigen-antibody reaction measurement data based on the output data from the rate measurement means Means for selecting output data from the conversion means or output data from the endpoint measurement means based on an output signal from the accuracy determination means.

<Action> According to the above immunoassay method, since the test solution is injected so as to be in contact with the reaction surface of the optical waveguide, the antigen-antibody reaction speed measurement data is obtained by the rate measurement method. By performing a linear regression until the reaction start time based on the data, an offset value at the time of starting the antigen-antibody reaction can be calculated. Therefore, after that, the measurement data at the time of saturation is obtained by the end point measurement method, and by calculating the difference from the offset value, the true measurement data due to the antigen-antibody reaction can be obtained.

According to the immunoassay method of the second invention, since the test solution is injected so as to be in contact with the reaction surface of the optical waveguide, antigen-antibody reaction rate measurement data is obtained by the rate measurement method. It can be determined whether a sufficient measurement result can be obtained by the 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. Conversely, if it is determined that sufficient measurement accuracy is not 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. it can. Therefore, thereafter, the measurement data at the time of almost saturation is obtained by the end point measurement method, and the true measurement data due to the antigen-antibody reaction can be obtained by calculating the difference from the offset value.

In the case where the regression interval is set sufficiently shorter than the reaction time constant and the offset value is calculated by performing a linear regression until 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 required operation time.

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

In the case of the immunoassay device having the above configuration, the test solution is injected so as to be in contact with the reaction surface of the optical waveguide, and then the antigen-antibody reaction rate measurement data is obtained by the rate measurement means. By means, it can be determined whether or not a sufficient measurement result can be obtained by the rate measurement method.

Then, when it is determined that sufficient measurement accuracy is obtained by the accuracy determination unit, the conversion unit and the selection unit perform the determination based on the obtained antigen-antibody reaction rate data.
Measurement data indicating the antibody reaction amount can be obtained. Conversely, 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. Can be calculated. Therefore, thereafter, the measurement data at the time of almost saturation is obtained by the end point measurement means, and the true measurement data due to the antigen-antibody reaction can be obtained by calculating the difference from the offset value.

<Example> Hereinafter, an example will be described in detail with reference to the accompanying drawings.

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

FIG. 1 is a flow chart showing one embodiment of the immunoassay method of the present invention. In the step, introduction of excitation light into the slab type optical waveguide (21) is started, and in the step, the rate at a preset sampling time is set. Start the measurement based on the measurement method. Then, in the step, if the test solution containing the antigen (23a) is diluted and the buffer of the reaction tank (22a) is replaced with a solution mixed with the fluorescently labeled antibody (23b), the antigen-antibody reaction proceeds. A signal corresponding to the reaction rate is obtained. In the antigen-antibody reaction curve exemplified in FIG. 2, the signal level at the start of the reaction, that is, the offset value, is determined based on the slope of the tangent of the reaction curve at the boundary between the time regions R2 and R3. In the step, the signal level at the start of the reaction, that is, the offset value, can be calculated by extrapolating the obtained signal. Therefore, after that, in the step, the measurement based on the end point measurement method is started, and after the step, the level of the measurement signal hardly changes, and in the step, the measurement signal whose level hardly changes and the offset value are set. , And in the step, an antigen-antibody reaction amount can be obtained based on the difference.

FIG. 2 is a diagram showing the temporal change of the obtained measurement signal. Although the buffer solution is initially contained in the reaction tank (22a), the fluorescence emitted from the slab type optical waveguide (21) itself is obtained. A measurement signal of a certain level (offset value due to the slab type optical waveguide) is obtained by light, Raman scattering, and the like (see a region R1 in FIG. 2). When the buffer solution was replaced with the test solution mixed with the fluorescently labeled antibody, the antigen-antibody reaction was not performed, but due to the fluorescently labeled antibody present near the reaction surface of the slab optical waveguide (21). The measurement signal rises sharply by the offset value (see time point R2 in FIG. 2), and thereafter, the level of the measurement signal gradually increases at a rate determined based on the amount of the antigen present in the test solution (FIG. 2). Middle area
After a certain period of time, an equilibrium state where the level of the measurement signal hardly changes (region R4 in FIG. 2).
reference).

Therefore, a measurement based on the rate measurement method is performed at the beginning of the antigen-antibody reaction, and a linear regression method, a non-linear regression method, a piecewise interpolation method, etc.
The offset value at the start of the antigen-antibody reaction can be obtained. More specifically, the signal intensity S (t) (see FIG. 3) at the beginning of the immune reaction can be expressed as an exponential function as a first approximation as follows.

S (t) = a + b exp (−t / τ) (where a and b are constants, τ is a reaction time constant depending on the activity of the reaction and can take a value of tens of seconds to several hundreds of seconds) In addition to the function, an approximate expression using a function such as S (t) = a + b exp (−t / τ) + c exp (−t / τ ′) is also possible. However, when regression calculations are performed using these approximation expressions, it takes a lot of time to calculate due to the non-linearity, and it is difficult to predict the time required for convergence. Absent. As a result of intensive studies in consideration of such points, it has been found that if the regression interval T satisfies a specific relationship with the reaction time constant τ, it is possible to suppress a decrease in the accuracy of the offset value obtained by linear regression. Was. That is, T
If << τ, linear regression of S (t) = at + b is possible, and if Tτ, regression by a linear polynomial such as parabolic regression of S (t) = a ＝ t + b is possible. Linear regression is the most preferable considering the stability and ease of calculation, but
The regression interval can be significantly shorter, resulting in reduced accuracy. Therefore, it is considered that the regression section T should be lengthened at the time of a low signal at which the decrease in accuracy is remarkable. Such a measure is effective when the main cause of the decrease in accuracy at the time of low signal is not a mismatch between the data and the regression curve but is random noise including data. In addition, since the immune reaction is not strictly a first-order reaction, but an apparent reaction time constant when the first-order reaction is approximated tends to be longer at a low signal, the regression interval T is also adapted from this point. It is found that it is effective to change to In this case, the section is determined by first regressing in a short regression section, and if the coefficient (gradient) in the regression section is equal to or less than a predetermined threshold, extending the regression section to a predetermined length. Based on the magnitude of the gradient in the first regression interval, a method of extending the regression interval in accordance with a predetermined conversion table or equation, the regression interval until the regression residual sum of squares or its average exceeds a predetermined value Can be exemplified as well as a method of appropriately combining these methods.

Also, since the level of the measurement signal is not saturated during the measurement based on the rate measurement method, the measurement based on the end point method may be performed after obtaining the offset value as described above. By calculating the difference between the almost saturated measurement signal and the offset value, the antigen-
A signal corresponding to the antibody reaction amount can be obtained.

Further, instead of storing the buffer solution in the reaction tank (22a) in advance, the reaction surface of the slab-type optical waveguide (21) can be kept in a dry state. Although the level becomes high as shown by the broken line in FIG. 2, after the fluorescently labeled antibody is mixed and the test solution is injected, the measurement signal changes in the same manner as described above, so that the highly accurate end point is similarly obtained. Measurement results can be obtained. In this case, the device and operation can be simplified by the amount that liquid replacement is not required.

<Example 2> Fig. 4 is a flowchart showing another example of the immunoassay method, in which the slab type optical waveguide (2
The introduction of the excitation light for 1) is started, and in step, measurement based on the rate measurement method at a preset sampling time is started. Then, in the step, if the test solution containing the antigen (23a) is diluted and the buffer of the reaction tank (22a) is replaced with a solution mixed with the fluorescently labeled antibody (23b), the antigen-antibody reaction proceeds. A signal corresponding to the reaction rate is obtained. Therefore, in the step, 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 by the rate measurement method, an immunoassay result is obtained by performing a predetermined operation based on the maximum value of the obtained signal in the step.

Conversely, if it is determined in the step that the rate measurement method does not provide sufficient measurement accuracy, in the step, the signal level at the start of the reaction, ie, the offset value, is obtained by extrapolating the obtained measurement signal. Can be calculated. Therefore, after that, wait until the level of the measurement signal hardly changes in the step,
In the step, the difference between the measurement signal whose level hardly changes and the offset value is obtained, and in the step, a predetermined calculation is performed based on the difference, whereby the antigen-antibody reaction amount can be obtained.

Therefore, in the case of this example, if the degree of the immune reaction is high, a highly accurate immunoassay can be performed in a short time by the rate measurement method, and if the degree of the immune reaction is low, the immunoassay can be obtained based on the rate measurement method. By extrapolating the reaction equation with the measured data obtained, an accurate offset value at the start of the reaction is obtained,
Using this offset value, highly accurate immunoassay can be performed by the end point measurement method. Note that the accuracy of the offset value obtained by extrapolation increases when the slope of the response curve is gentle and decreases when the slope of the response curve is steep. However, the measurement based on the end point measurement method is performed using the offset value. This is only when the slope of the response curve is gentle, so there is no inconvenience.

<Embodiment 3> Fig. 5 is a block diagram showing an embodiment of the immunoassay apparatus of the present invention, which is a detector which receives fluorescent light which changes according to the amount of antigen-antibody reaction and converts it into an electric signal. (1), a sampling circuit (2) for sampling a signal output from the detector (1), a regression section setting section (3) for setting a regression section T, a sampled signal and a set regression section A gradient calculating unit (4) for calculating a gradient of a straight line in a set regression section T based on T, and a comparing unit (5) for determining whether the calculated gradient is equal to or less than a preset threshold. An offset value calculating section (6) for performing an offset value by performing a linear regression based on the sampling signal in the regression section T, and an equilibrium determining section (7) for determining whether or not the sampling signal is balanced. Sample at equilibrium A reaction amount calculation unit (8) for calculating an antigen-antibody reaction amount based on the signaling signal and the calculated offset value;
The regression interval T to be set by the regression interval setting unit (3) is changed to a preset regression interval on condition that the comparison unit (5) outputs a determination result indicating that the value is equal to or less than the threshold value, A control unit (9) for operating the offset value calculation unit (6) based on the changed regression section. Here, the sampling circuit (2) and the gradient calculator (4) constitute a rate measuring means for obtaining antigen-antibody reaction measurement data based on the rate measuring method. The equilibrium discrimination unit (7) and the reaction amount calculation unit (8) obtain reaction measurement data when the antigen-antibody reaction is substantially equilibrated, and calculate the difference between the obtained reaction measurement data and the offset value. It constitutes an endpoint measuring means for outputting as antigen-antibody reaction measurement data.

The operation of the immunoassay device having the above configuration is as follows.

First, the regression section setting section (3) sets a regression section T sufficiently shorter than the reaction time constant τ. Then, the signals sampled by the sampling circuit (2) are sequentially acquired, and the gradient of the linear regression equation is calculated by the gradient calculation unit (4) based on the sampling signals in the range of the regression section T, and the calculated gradient is set in advance. The comparison unit (5) determines whether the difference is equal to or less than the threshold value.

When it is determined that the calculated gradient is larger than the threshold value, the offset value is calculated by performing a linear regression by the offset value calculation unit (6) based on the sampling signal in the regression section T. Thereafter, the equilibrium discrimination section (7) judges whether or not the sampling signal is equilibrated, and the reaction amount calculation section (8) uses the reaction amount calculation section (8) based on the sampling signal when the equilibrium is judged and the calculated offset value. -The amount of antibody reaction can be calculated.

Conversely, when it is determined that the calculated gradient is equal to or smaller than the threshold, the control unit (9) changes the regression section to a long regression section set in advance, and performs an offset based on the changed regression section. The antigen-antibody reaction amount can be calculated by performing the value calculation operation, the equilibrium determination operation, and the reaction amount calculation operation.

That is, the offset value can be calculated more accurately than in the conventional apparatus, and highly accurate immunoassay can be performed by the end point measurement method using the calculated offset value.

<Embodiment 4> Fig. 6 is a block diagram showing another embodiment of the immunoassay apparatus of the present invention. The difference from the embodiment of Fig. 5 is that the gradient of the response curve is determined based on the sampled signal. The maximum value extraction unit (1
0) and a reaction amount calculation unit (11) for calculating an antigen-antibody reaction amount based on the maximum gradient. A linear regression equation when the regression interval is changed to a preset length The control unit (9) operates the comparison unit (5) to determine whether or not the gradient of the reaction amount is equal to or less than a predetermined threshold, and any one of the reaction amount calculation units based on the determination result in this case. (8) Selection unit (12) for selecting the calculation amount from (11)
Is further provided. In this example,
The sampling circuit (2), the gradient calculator (4) and the maximum value extractor (10) constitute a rate measuring means for obtaining antigen-antibody reaction measurement data based on a rate measuring method. The equilibrium discrimination unit (7) and the reaction amount calculation unit (8) obtain reaction measurement data when the antigen-antibody reaction is substantially equilibrated, and calculate the difference between the obtained reaction measurement data and the offset value. It constitutes an endpoint measuring means for outputting as antigen-antibody reaction measurement data. Further, the comparing section (5) constitutes an accuracy judging means for judging whether or not the measuring accuracy is sufficient based on the antigen-antibody reaction measurement data obtained by the rate measuring means.

Therefore, in the case of this embodiment, if the gradient of the linear regression equation is greater than the threshold in both the regression section sufficiently shorter than the reaction time constant and the preset long regression section, the maximum value extraction is performed. The antigen-antibody reaction amount calculated by the reaction amount calculation unit (11) based on the maximum gradient extracted by the unit (10) may be selected by the selection unit (12), and it is necessary to wait until the sampling signal equilibrates. The time required for the immunoassay can be shortened because there is no data. In addition, the immunoassay accuracy can be sufficiently increased.

Conversely, if the slope of the linear regression equation is equal to or less than the threshold value in any of the regression sections, highly accurate immunoassay can be achieved based on the end point measurement method as in the above embodiment.

In summary, the immunoassay by the end-point assay can be performed only when sufficient measurement accuracy cannot be obtained by the rate assay, and the time required for performing immunoassay on a large number of test solutions is increased. In addition to shortening, immunoassay with sufficient accuracy can be achieved.

The present invention is not limited to the above embodiment. For example, the conversion table set by the regression section setting unit (3) may be converted into a conversion table corresponding to the magnitude of the gradient in the initial regression section. In addition to the above, the regression interval can be extended until the sum of the residual squares of the regression or its average becomes equal to or more than a predetermined value. Various design changes can be made without departing from the spirit of the invention.

<Effects of the Invention> As described above, the first invention calculates the offset value, which has been likely to be inaccurate in the past, based on the reaction speed measurement data obtained by the rate measurement method. By performing a linear regression, an accurate offset value can be calculated in a short time required for the calculation, and as a result,
There is a unique effect that the measurement accuracy by the point measurement method can be improved.

In the second invention, when sufficient accuracy is 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 measurement data obtained by the rate measurement method. This has a specific effect that the measurement accuracy by the end point measurement method can be improved.

The third invention has a unique effect that the time required for the operation can be shortened and adapted to the real-time processing.

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

According to a fifth aspect of the present invention, when sufficient accuracy is obtained by the rate measurement method, the 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. This has a specific effect that the measurement accuracy by the end point measurement method can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart showing one embodiment of the immunoassay method of the present invention, FIG. 2 is a diagram showing a temporal change of an obtained measurement signal, FIG. 3 is a diagram showing a signal change in an initial stage of a reaction in detail, FIG. FIG. 4 is a flowchart showing another embodiment of the immunoassay method of the present invention. FIG. 5 is a block diagram showing one embodiment of the immunoassay device of the present invention. FIG. 6 is another embodiment of the immunoassay device of the present invention. FIG. 7 is a block diagram showing an embodiment, and FIG. 7 is a perspective view showing a schematic configuration of an optical measurement device used for immunoassay. (2) ... a sampling circuit forming rate measuring means (4) ... a gradient calculating section forming rate measuring means (5) ... a comparing section as accuracy determining means (6) ... offset value calculation , (7) ... equilibrium discriminating unit constituting end point measuring means, (8) ... reaction amount calculating unit constituting end point measuring means, (10) ... maximum value constituting rate measuring means Extraction unit, (11) ... reaction amount calculation unit as conversion means, (12) ... selection unit

Claims (5)

(57) [Claims] 1. A method for obtaining reaction rate measurement data based on a rate measurement method, calculating an offset value at a reaction start time based on the obtained measurement data, and applying an end point measurement method using the calculated offset value. In the immunoassay method based on immunoassay, the regression interval is set sufficiently shorter than the reaction time constant, and linear regression is performed until the reaction start time based on the reaction rate measurement data obtained by the rate measurement method, and the offset value is calculated. An immunoassay method characterized by calculating 2. An immunoassay based on a rate measurement method is performed to obtain reaction rate measurement data, it is determined whether or not sufficient measurement accuracy is obtained, and when it is determined that a sufficient measurement result is obtained. Uses the obtained reaction rate measurement data as it is, and conversely, if it is determined that sufficient measurement accuracy cannot be obtained, the offset at the reaction start time is determined based on the reaction rate measurement data obtained by the rate measurement method. An immunoassay method comprising calculating a value and using reaction measurement data based on an end point measurement method using an offset value. 3. The above patent wherein the regression interval is sufficiently shorter than the reaction time constant, and the offset value is calculated by performing a linear regression until the reaction start time based on the reaction rate measurement data obtained by the rate measurement method. The immunoassay method according to claim 2. 4. The immunoassay method according to claim 2, wherein if the result of the immunoassay based on the rate measurement method is smaller than a predetermined threshold value, it is determined that sufficient measurement accuracy cannot be obtained. 5. A rate measuring means for obtaining antigen-antibody reaction rate measurement data based on a rate measuring method.
An accuracy determining means (5) for determining whether or not the measurement accuracy is sufficient based on the antigen-antibody reaction rate measurement data obtained by the rate measuring means (2), (4) and (10); On condition that an output signal from the accuracy determination means (5) indicating that the determination is sufficient is supplied,
Offset value calculating means (6) for extrapolating an antigen-antibody reaction curve until the reaction start time to calculate an offset value using the antigen-antibody reaction rate measurement data obtained by the rate measuring means (2) and (4); Endpoint-measurement means (7) which obtains antigen-antibody reaction rate data when the antigen-antibody reaction is substantially equilibrated, calculates the difference between the obtained reaction rate data and the offset value, and outputs the result as antigen-antibody reaction measurement data (7). And (8) converting means for obtaining antigen-antibody reaction rate data based on output data from the rate measuring means (11).
Selection means (1) for selecting output data from the conversion means (11) or output data from the end point measurement means (8) based on an output signal from the accuracy determination means (5).
2) An immunoassay device comprising: