[Clinical importance of hepatitis B antigen (author's transl)]

The clinical importance of the hepatitis B antigen (HBsAg) is based mainly on the differentiation between different courses of inflammatory liver diseases and/or nonvirus induced diseases of the liver. Epidemiologic studies have shown that beside a parenteral inoculation there is a possibility of a non-parenteral inoculation. Furthermore, there is evidence that the sporadic hepatitis is more commonly hepatitis B. Epidemiologic investigations revealed that clinically healthy HBsAg carriers, the "carrier" status in immunodeficiency syndromes and the natural circulation of the hepatitis B virus are of major interest. The demonstration of HBsAg enables us to characterize some diseases which show associations to hepatitis B virus, but where the pathogenic role of HBsAg/Ab immunocomplexes is questionable. Furthermore, it was possible by the detection of HBsAg to establish newer therapeutic and preventive interventions of virus B hepatitis.