Evaluation of three reverse passive haemagglutination methods and two radioimmunoassay tests to be used for the detection of hepatitis B surface antigen.

Sensitivity and specificity of three reverse passive haemagglutination (RPHA) methods (Hepanosticon, Hepatest and Auscell) and of two solid-phase radioimmunoassays (RIA) (Austria-125 and Ausria II-125), all phase 3 tests for hepatitis B surface antigen (HBSAg), were compared with the sensitivity and specificity of an immunoelectroosmophoresis (IEOP) technique. By titration experiments the RPHA methods were shown to be 5-20 times more sensitive than the IEOP test, while RIA detected 5-10 times lower concentrations of antigen than the most sensitive RPHA test. In a study of sera drawn consecutively from patients with hepatitis B infections, the increased sensitivity of the test methods was according to the following order: IEOP, Hepanosticon, Hepatest, Ausria-125, Auscell, Ausria II-125. There were significant differences between all the methods except for that between Ausria-125 and Auscell. IEOP did not detect any false positives. If, however, RPHA tests were used, the incidence of nonspecific positive reactions would be in the range 0.5%-0.9%. The advantages of the individual test methods are discussed.