[Incidence of hepatitis surface antigen among all the blood donors of the blood banks of the Venezuelan Institute of Social Security in the federal district].

The presence of H Bs-Ag was studied by means of counterimmunoelectrophoresis in the sera of 879 voluntary donors who gave blood between May and September 1974 at the federal District's blood banks of the Venezuelan Institute of Social Security. Eight hundred twenty-eight were male and fifty one female. Five sera samples were positive HBs-Ag which represents an incidence of 0.56%. A bibliographic review of the subject is made. The necessity of making mandatory the determination of HBs-Ag in all blood prior to transfusion is emphasized.