Hepatitis B surface antigen and antibody in asymptomatic blood donors.

Seventy-two volunteer blood donors who had hepatitis B surface antibody (anti-HBS) were studied and compared with 115 carriers of hepatitis B surface antigen (HBSAg). Anti-BHS-positive donors gave a history of greater possible exposure to hepatitis B virus, there was a lower male-female ratio, and they had a much lower frequency of abnormal hepatic function test results. Those who were positive by counterimmunoelectrophoresis (CIEP), which indicated a high titer of antibody (greater than 1:2,000 as measured by passive hemagglutination assay [PHA], also had an ethnic origin similar to that of the donor panel, ie, predominantly Canadian and northern European. The HBSAg carriers, on the other hand, had a high frequency of origin from Mediterranean and Far Eastern countries. Low-antibody-titer (positive PHA but negative CIEP) donors had ethnic origins that more closely approximated those of HBSAg carriers.