Frequency of hepatitis B antigen in blood donors.

Routine testing of all blood donations for hepatitis B antigen by counter-immunoelectrophoresis was started in April 1971. The frequency of HBAg carriers among apparently healthy volunteer blood donors in the Toronto Centre of the Canadian Red Cross Blood Transfusion Service was 15 in 10,000 with a male:female ratio of 6:1. Excluding penitentiary inmates, the highest incidence was among young, male, non-Anglo-Saxon city dwellers.A system of notification of HBAg-positive donors was developed, through which a carrier is referred to a special clinic for clinical and pathological evaluation.A survey of hospital patients indicated an incidence of HB antigen 3.5 times that of our healthy donor population. A comparison of the number of post-transfusion hepatitis cases occurring before and after the commencement of routine testing for HBAg showed a marked reduction in reported cases in 1971.