No abstract

No abstract

SUMMARY Sera from two blood donors, one of whom was implicated in a case of post-transfusion hepatitis B, were found to be positive for anti-HBc and negative for HBsAg by conventional radioimmunoassay and were retested for HBsAg after concentration (pepsin digestion and polyethylene glycol precipitation). The presence of occult HBsAg was confirmed in both. These observations have implications for blood transfusion, and wider studies of anti-HBc in blood donors are recommended before the introduction of routine screening for anti-HBc and exclusion of the positive donors from blood donation.

The results of a pilot study on the prevalence of anti-HBc in HBsAg negative volunteer blood donors are presented. Two techniques for anti-HBc determination were compared--radioimmunoassay (RIA) and indirect immunofluorescence (IF). In a panel of 56 sera with known HBV markers, RIA was found to be significantly more sensitive than IF, and both techniques were specific. Out of 2,000 HBsAg negative blood donor sera tested by RIA, 46 (2.3%) were found positive for anti-HBc. In 24/24 sera, the specificity of the anti-HBc was confirmed. Also 37/46 (80.4%) anti-HBc positives were found positive for anti-HBs, leaving 9/2,000 (0.4%) blood donors positive only for anti-HBc. It is concluded that it would be premature to advocate the introduction of anti-HBc as a routine screening test of blood donors.

Anti HBs, anti-HBc and anti-HBe were tested in blood donors negative for HBsAg by radio- and enzyme-immunoassay. In this population 6.4% of the donors were positive for at least one type of antibody to HBV: 4.0% for anti-HBs, 2.3% for anti-HBc and 4.3% for anti-HBe. Two sera (0.2%) were exclusively positive for anti-HBc, eight sera (2.2%) were weakly positive only for anti-HBe. Further studies of the infectivity of such samples might be of interest.