Transmission of hepatitis B virus 2 months prior to hepatitis surface antigen positivity of donor blood

An hepatitis surface antigen(HBsAg)-negative donation transmitted hepatitis B virus (HBV) of the very common genotype A/HBsAg subtype adw2 to the recipient of the erythrocyte concentrate. Two months later the donor became borderline HBsAg-positive. The infectious donation was tested retrospectively by real time PCR and contained approximately 2,000 viral genomes/ml, an amount which would have been well detectable by minipool nucleic acid amplification test (NAT) for HBV DNA at the usual detection limit of 1,000 copies/ml. The case shows that the HBsAg-negative, HBV DNA-positive phase may be longer than previously believed and that HBV DNA screening at a sensitivity achievable by minipool NAT testing would have prevented transmission.