ABSTRACT
In order to investigate the relationship of hepatitis A antigen to viral hepatitis, a prospective study was carried out on 97 patients admitted to Fairfield Hospital, Melbourne, with suspected viral hepatitis, and 3 of their family contacts. Evidence of infection with hepatitis A virus was obtained by detecting hepatitis A antigen in stools, and/or antibody to it in sera, by immune electron microscopy. Infection with hepatitis B virus was determined by testing for hepatitis B surface antigen and antibody in serum, by solid phase radioimmunoassay. Sixteen patients were found to have diseases other than viral hepatitis and 2 patients (child contacts) suffered no illness. There was clinical and/or biochemical evidence compatible with viral hepatitis in 82 patients, of whom 35 were confirmed as having hepatitis A and 31 as having hepatitis B infections. In the remaining 16 patients there was no evidence of infection with either hepatitis A or B virus. It is possible that some of these patients may have been infected with viral agents as yet unidentified.