Positive ample Negative sampl FiG 1. Solid phase membrane(e-g. a 96well plate)precoated PIG. 2 Serum samples are added and incubated to allow spe- with antigen ursing a coating buffer that enhances binding Sites cific antibodies to bind to specific antigen, Antibodies that do unoccupied by the antigen are blocked with a blocking buffer not recognize and bind specifically to the antigen remain um. to prevent nonspecific binding of sample. bound 反应板上包被的抗原 加入不同稀释度血清反应板上包被的抗原 加入不同稀释度血清