Application of microtiter solid-phase radioimmunoassay to the determination of hepatitis B e antigen

Microtiter solid-phase radioimmunoassay (micro-SPRIA) was applied to the detection of hepatitis B e antigen (HBeAg) in the serum. Antibody against HBeAg to coat the microtiter plate and for radiolabeling was obtained from the serum of asymptomatic carriers of hepatitis B surface antigen by an affinity column of partially purified HBeAg. The micro-SPRIA was sensitive and could be performed without prior concentration of the test serum. HBeAg was detected in 21 (35%) out of 60 serum samples positive for hepatitis B surface antigen, all of which were negative by the conventional immunodiffusion method even after they had been concentrated threefold.