Detection HBsAg mutants by immunoassays

HBV surface antigen (HBsAg) is the most important marker for the laboratory diagnosis of hepatitis B virus infection. Mutants can emerge in patients as a result of selective pressure. Since almost all diagnostic assays for detection of HBsAg rely on antibodies against the major epitope "a" determinant, amino acid (aa) substitutions in this region could potentially lead to diagnostic failures. The new generation of HBsAg assays uses mixtures of monoclonal antibodies in order to recognize the known S gene mutants and ideally should be sensitive enough to detect the smallest amounts of HBsAg present in lowlevel carriers.