JPH01313737A - Inspection device for body to be inspected - Google Patents

Abstract

PURPOSE:To detect a latex grain lump with high accuracy even by a small quantity of sample liquid by allowing an irradiating light to transmit through the sample liquid in an optical cell plural times. CONSTITUTION:The sample liquid of a latex suspension of prescribed concentration stored in an optical cell 2 is irradiated by a laser beam emitted from a light source 1. The light which has transmitted through the sample liquid is reflected by a mirror 3 and the optical path is loop back, and the sample liquid is irradiated by the light again. The light which has transmitted through the sample liquid again is detected as to its light intensity by a photodetector 5 through a condensing lens 4, and inputted to an arithmetic circuit 10. In the arithmetic circuit 10, absorbance is calculated from the transmitting light intensity which has been detected, and an immunity reaction inspection is executed by a well-known method.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a specimen testing device used for detecting trace amounts of antigen or antibodies as an immunodiagnostic method, for example, by optically measuring latex agglutination reaction to detect antigens or antibodies. The present invention relates to a device for detecting antibodies.

[Prior Art] A suspension in which a test sample (e.g. serum) containing an antigen or antibody is added to a suspension in which insoluble carrier particles (e.g. latex particles) sensitized with a specific antibody or antigen are suspended at a predetermined concentration. Prepare and irradiate the irradiation light. At that time, if the latex particles in the suspension are in a dispersed state, light with a wavelength much longer than the particle diameter is transmitted without being greatly affected by the presence of the latex particles, as shown in FIG. 7(a). That is, transmitted light with high intensity can be obtained. However, due to the antigen-antibody reaction, the sensitized latex binds to each other to form particle agglomerates with large particle diameters, and when the particle diameter of the aggregated particle agglomerates approaches the wavelength of light, the particles form as shown in FIG. 7(b). The light is scattered and the transmitted light intensity is reduced. There is a reaction rate analysis method that measures and analyzes the concentration of the suspension from the reaction rate that captures the temporal change in the intensity of transmitted light, and measures the intensity of transmitted light and scattered light of the suspension after the reaction is completed. Reaction termination analysis methods have been generally known for a long time. This has made it possible to measure the amount of a specific antigen or antibody in a test sample, and has been used for immunological diagnosis.

As an example, as shown in FIG. 5, a latex particle suspension of a predetermined concentration, which is a sample liquid, is stored in an optical cell 14, which is a transparent container, and a laser beam is irradiated onto it from a laser light source 11. The light intensity is detected by the photodetector 16 to determine the absorbance, and the size and amount of the reaction mixture in the sample solution can be detected, thereby determining the aggregation state of the latex particles and determining the amount of the target antigen or antibody. Can be quantified.

[Problem that the invention seeks to solve] However,
When detecting the size of latex particle aggregates by the absorbance of a latex particle suspension as in the conventional example above,
As shown in Figure 6, as the particle size of the latex particle agglomerates increases, the absorbance increases linearly, but when the wavelength of the irradiated light is short, such as 400 nm or 600 nm, the latex particle size remains constant. If this value is exceeded, the absorbance graph will decrease, and two particle sizes will correspond to the absorbance determined from the transmitted light intensity, making it difficult to judge which particle size is the correct value. There wasn't. Therefore, when using light with a long wavelength such that the absorbance graph does not decrease, for example, light with a wavelength of 800 nm, the change in absorbance becomes small when the particle size exceeds a certain value (approximately 1.0 μm). However, there was a problem in that the measurement sensitivity was poor.

The present invention aims to solve the above-mentioned problems, that is, to provide a sample testing device with high measurement sensitivity. The object of the present invention is to provide a sample testing device that can simultaneously perform highly sensitive measurements even with a small amount of sample liquid.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in a specimen testing device that measures the state of aggregation of particles in a sample liquid by irradiating the sample liquid with irradiation light and measuring the intensity of the transmitted light. , comprising means for causing the irradiation light to pass through the sample liquid multiple times.

[First embodiment Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of a first embodiment of the present invention, in which laser light emitted from a laser light source 1 (semiconductor laser with a wavelength of 800 nm) emits a latex suspension of a predetermined concentration stored in an optical cell 2. The sample liquid is irradiated. The light that has passed through the sample liquid is reflected by the mirror 3, the optical path is turned back, and the sample liquid is irradiated again. The light intensity of the light that has passed through the sample liquid again is detected by the photodetector 5 via the condensing lens 4, and is input to the arithmetic circuit 10. In the arithmetic circuit 10, absorbance is calculated from the detected transmitted light intensity, and an immune reaction test is performed using a well-known method.

In the example, the irradiation light passes through the sample liquid twice, thereby doubling the transmission distance. The relationship between absorbance and particle size at this time is shown in Figure 2, where the overall slope of the graph is approximately twice that of the one-time transmission. When the latex particle size was 1.0 μm or more, the slope of the graph was small and it was difficult to determine the accurate particle size, but the slope of the graph is about twice as large, making it easier to determine the latex particle size. In other words, the measurement sensitivity is also approximately twice as high.

In this example, the irradiated light is transmitted through the sample liquid twice by providing one mirror and reflecting it, but it is also possible to provide a plurality of mirrors and cause the irradiated light to pass through the sample liquid multiple times. The sensitivity can be further increased. As a result, even if the optical cell 2 is small and the sample liquid is small, highly sensitive measurement is possible.

[Example 2] FIG. 3 is a block diagram of a second embodiment of the present invention.

One side of the optical cell 2 is coated with a mirror reflection part 9, and the irradiated light that has passed through the sample liquid is reflected by the mirror reflection part 9. As a result, the same effects as in the first embodiment can be obtained.

[Example 3] FIG. 4 is a block diagram of a third embodiment of the present invention.

A half mirror 6 is placed between the optical cell 2 and the mirror 3 in the optical path.
is provided, and the light reflected by the half mirror 6 is received by a photodetector 8 via a condenser lens 7. The output of the photodetector 8 is input to the arithmetic circuit 10 similarly to the photodetector 5. In this configuration, the light that has passed through the sample liquid only once is detected by the photodetector 8.
The light that has passed through the sample liquid twice is detected by the photodetector 5. Of course, it is also possible to provide three or more sets of mirrors 3 and half mirrors 6 and extract the output from each for selective detection.

This allows you to select the output that provides the optimal amount of light when the sample liquid is passed through the sample liquid multiple times and the optical path length of the transmitted light becomes longer, resulting in a smaller amount of light, which increases the influence of noise and worsens the S/N ratio. can be measured.

[Effects of the Invention] As described above, according to the present invention, by transmitting irradiation light through the sample liquid in the optical cell multiple times, it is possible to detect latex particle clusters with high accuracy even with a small amount of sample liquid, thereby detecting antigens or antibodies. The amount of can be detected with high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the first embodiment of the present invention, Fig. 2 is a graph showing the relationship between latex particle size and absorbance in the embodiment, Fig. 3 is a block diagram of the second embodiment, and Fig. 4 is a graph showing the relationship between the latex particle size and absorbance in the embodiment. The configuration diagram of the third embodiment, Figure 5 is the configuration diagram of the conventional example, Figure 6 is a graph showing the relationship between latex particle size and absorbance at various wavelengths, and Figure 7 is an explanatory diagram of the measurement principle. Yes, in the figure: 1... Semiconductor laser, 2... Optical cell, 3... Mirror, 4... Condensing lens, 5... Photodetector, 6...
・Half mirror 110...Arithmetic circuit/rho

Claims (1)

[Claims] 1. A specimen testing device that measures the state of aggregation of particles in a sample liquid by irradiating the sample liquid with irradiation light and measuring the transmitted light intensity, including means for transmitting the irradiation light through the sample liquid multiple times. A sample testing device featuring: