American Red Cross experience with routine testing for hepatitis B core antibody.

The implementation of routine testing of blood donations for hepatitis B core antibody (anti-HBc) has allowed the characterization of the performance of the test in a large number of samples from apparently healthy individuals. This study reports the experience of the American Red Cross in testing 2.3 million donors for anti-HBc. The test protocol reproducibly identified a distinct population of donors. The anti-HBc-positive rate varied by region of the continental United States and by the time of year. In a case-control study, 85 percent of subsequent donations from anti-HBc-positive donors were anti-HBc positive. The predictions made in an earlier pilot study regarding the performance and impact of the test were borne out.