The emerging pattern of post-transfusion hepatitis.

The exclusion of commercial and hepatitis B surface antigen (HBs Ag)-positive donors, as measured by counterelectrophoresis, has markedly reduced the frequency of post-transfusion hepatitis (PTH). A further, significant reduction in type-B PTH can be achieved by prescreening donors for HBs Ag by solid-phase radioimmunoassay (RIA); When a voluntary donor population, pretreated by RIA, is used, approximately 90 per cent of residual hepatitis is serologically unrelated to either the type-A or type-B hepatitis viruses. Similarly, cytomegalovirus and the Epstein-Barr virus are not serologically implicated in "non-A, non-B" hepatitis. Additional human hepatitis virus(es) may exist.