October 11, 1993

Significance of Isolated Hepatitis B Core Antibody in Blood Donors

Author Affiliations

From the Departments of Pathology (Dr Schifman) and Internal Medicine, Division of Gastroenterology (Dr Sampliner), Tucson (Ariz) Veterans Affairs Medical Center and University of Arizona Health Sciences Center, Tucson, and Southern Arizona American Red Cross Blood Center, Tucson (Dr Rivers and Ms Krammes).

Arch Intern Med. 1993;153(19):2261-2266. doi:10.1001/archinte.1993.00410190107012

Background:  About 25% of blood donors who test positive for antibody to hepatitis B core antigen (anti-HBc) have no other positive hepatitis B serologic results. Because of the potential importance and diagnostic uncertainty of this test result, we studied its significance by assessing the serologic response to hepatitis B vaccine in donors with an isolated anti-HBc pattern.

Methods:  Specimens from 300 blood donors that were positive for anti-HBc by enzyme immunoassay were tested for anti-HBc by radioimmunoassay and for antibody to hepatitis B surface antigen (anti-HBs). A subgroup of 37 were further studied after administration of hepatitis B vaccine and compared with 34 similarly vaccinated ageand sex-matched seronegative controls. Measurements of anti-HBs were made at vaccination and 1, 2, 4, 8, 25, and 30 weeks after initial vaccination.

Results:  Among 300 donors who tested positive for anti-HBc by enzyme immunoassay, the radioimmunoassay for anti-HBc was negative in 76 (25.3%) and the test for anti-HBs was negative in 104 (34.7%). Significant differences were observed for radioimmunoassay anti-HBc and antiHBs titers, alanine aminotransferase, and male-female ratios between four distinct serogroups (A through D) defined by the combination (positive/negative) of radioimmunoassay anti-HBc and anti-HBs results. No significant differences between the study and control groups were observed in the magnitude of anti-HBs responses at any of the six postvaccine testing periods.

Conclusions:  Isolated anti-HBc in US blood donors is usually a false-positive result, regardless of the titer.(Arch Intern Med. 1993;153:2261-2266)