False-positive results with hepatitis B virus DNA dot-hybridization in hepatitis B surface antigen-negative specimens

Three serum samples derived from healthy hepatitis B surface antigen-negative subjects were found to be reactive for hepatitis B virus (HBV) DNA sequences when assayed by DNA dot-hybridization. All three results were shown to be due to the presence of sequences which reacted with residual bacterial plasmid vector sequences in the DNA probe, and no evidence of HBV markers was demonstrated in the sera. This is the first report of a false-positive result with the HBV DNA dot-hybridization assay.