An ELISA assay is an immunoassay technique used in the detection of disease that detects the presence of an antigen in a biological sample. ELISA, like other types of immunoassays, uses highly specific antibody and antigen interactions to detect the target antigen. The specific principles of it can be seen as follows to help you understand better:

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• The working principle of ELISA is the interaction between antigen and antibody. When the interaction occurs, the substrate and enzyme are combined and transformed to obtain the result.

• ELISA assay mainly uses antigens or antibodies to bind to the surface of a certain solid-phase carrier, and maintains their immunological activity.

• The antigen or antibody is linked with an enzyme to form an enzyme-labeled antigen or antibody, which not only retains its immunological activity, but also retains the activity of the enzyme.

• During the determination, the test specimen and the enzyme-labeled antigen or antibody react with the antigen or antibody on the surface of the solid-phase carrier to form an antigen-antibody complex according to different steps and procedures.

• The antigen-antibody complex formed on the solid-phase carrier is separated from other substances by washing, and finally the amount of enzyme bound to the solid-phase carrier is proportional to the amount of the substance to be tested in the sample.

• Add the substrate of the enzyme reaction, it will be catalyzed by the enzyme on the solid phase carrier to produce a color change, the amount of the colored product is directly related to the amount of the test substance in the sample, and qualitative or quantitative analysis can be performed according to it, so that Determine the presence and content of the substance to be tested in the sample, and provide useful antigen and antibody concentration measurements. To increase the sensitivity of the assay, ELISA plates should be coated with high-affinity antibodies.