| abstract |
An enzyme immunoassay is provided for the measurement of antigen, with improved sensitivity. Said immunoassay comprises the steps of: (1)reacting [A] an immune-complex, obtained by reacting, at one time, (a) the antigenic substance, (b) an immobilized first antibody recognizing the antigenic substance and (c) a second antibody recognizing the antigenic substance originating from a different animal species, with [B] an enzyme-labelled third antibody recognizing immunoglobulin originating from the same animal species as said second antibody; (2) separating a solid phase from the liquid phase; and (3) measuring the amount of said enzyme present in the solid phase by means of the enzyme activity. The antigen may be carcinoembryonic antigen, thyroid stimulation hormone, human chorionic gonadotropin beta sub unit or hepatitis B virus. |