A competitive inhibition reaction is launched between biotin labeled T4 and biotin unlabeled antigens (Standards or samples) with the pre-coated antibody specific for T4.

• 用纯化的抗体包被微孔板，制成固相抗体，固相抗体与一定量的生物素标记的T4和非标记抗原(标本或标准品)进行竞争抑制反应，待测定的标本量越多，抗体与生物素标记的T4结合就越少，反之结合就多。