Hepatitis B antigen in screened blood units for transfusion in renal dialysis patients.

Blood units for transfusion are screened routinely in Ontario for the presence of hepatitis B antigen (HB-Ag) by counter-immunoelectrophoresis (CIEP). Since the radioimmunoassay (RIA) method is more sensitive for this purpose we used it to test blood units delivered to the hospital's Renal Dialysis Unit in order to determine if HB-Ag-carrying blood donors were being missed by the less sensitive CIEP method.Out of the 606 blood units tested, eight were found to contain HB-Ag, an incidence of 13 out of 1000 donors. This finding indicates that the counter-immunoelectrophoresis method is insufficiently sensitive as a safe screening method for detection of hepatitis antigen.