Evaluation of assay methods for hepatitis-associated antigen.

Assay methods for hepatitis-associated antigen (HAA) were evaluated for sensitivity, or reproducibility, or both in a series of three trials in which both research and service-oriented laboratories participated. Agar-gel diffusion (AGD) methods were found to be the least sensitive and reproducible of the commonly employed assay methods. Complement fixation (CF) tests were consistently more sensitive than either AGD or counterelectrophoresis (CEP) methods for detection of HAA. With judicious choice of the antibody reagent, sensitivity of CEP techniques was equivalent to CF methods of HAA detection. None of the three major assay methods (AGD, CEP, or CF) compared in this study were capable of consistently detecting HAA when it was present in relatively low concentrations in human serum.