Infectivity of blood components with low hepatitis B virus DNA levels identified in a lookback program.

Background: Japanese Red Cross (JRC) blood centers implemented anti-hepatitis B core antigen (HBc) screening in 1989 and 50-minipool (MP)-nucleic acid testing (NAT) in 2000. A systematic lookback study has been conducted to determine the hepatitis B virus (HBV) transmission risk of donations drawn in the pre-hepatitis B surface antigen (HBsAg) and/or MP-NAT window phase and by donors with occult HBV infection.

Study Design And Methods: JRC blood centers have been storing aliquots of every blood donation since 1996.