Minutes of the fourth meeting of the reconvened advisory group on testing for the presence of Hepatitis B Surface Antigen and its antibody, held on 6th March 1980. Of note non-A non-B Hepatitis - work of the HRC Group, progress towards a British Standard, viral hepatitis markers in blood donors and patients with a history of jaundice, factor VIII and IX associated transfusion hepatitis in the UK, the antigen positive donor.