PURPOSE: To detect presence and absence of an antibody or an antigen by bringing inspection body liquid into contact with an insoluble component together, separating an insoluble phase from a liquid phase after contact, and examining a labeled compound in one phase or both the phases.

CONSTITUTION: Human immunity incompleteness virus(HIV) has two groups of HlV-1 and HlV-2. For instance, HlV-1 antigen is connected on a solid phase and HIV-1 is used as composite in detection of anti-HIV-1 antibody. In this case, for instance, even if a small quantity of an antibody for HIV-2 is contained in inspection body liquid, the antibody for HIV-2 is not detected. This indicates that anti-HIV-1 composite of strong connection force overcomes in competition with HIV-2 antibody and is connected with the connection position of HIV-1 antigen. When HIV-2 antigen is connected on the solid phase in place of HIV-1 antigen and labeled HIV-1 antibody is used as the composite, both of the antibody existing in blood serum and HIV-2 antibody are detected. Thereby both the antibodies, anti-HIV-1 and anti-HIV-2 can be detected.