Total screening of blood donations for Australia (hepatitis associated) antigen and its antibody.

During a period of one year all of 105,724 blood donations were tested for Australia (Au) antigen and its antibody by rapid immunoelectro-osmophoresis-86 (1 in 1,229) were positive for antigen and 67 (1 in 1,578) positive for antibody. Second donations by previously negative donors reduce the overall incidence of positives. Men prisoners have a significantly higher incidence of Au antigen (1 in 153) than non-institutionalized men (1 in 803). The latter have a significantly higher incidence of antigen than women (1 in 2,019). Only one antigen-positive donor was incubating acute viral hepatitis. Failure to detect one strong and one weak antigen was responsible for two cases of posttransfusion Au-antigen-positive hepatitis.