Abstract: Objective To track the voluntary blood donors who showed positive hepatitis B virus DNAs to ensure blood transfusion safety. Methods 22 518 cases of blood donors were subjected to repeated ELISA testing and NAT detection. The NAT-positive samples that showed negative HBsAg by repeated ELISA but positive HBsAg by single ELISA were checked by both DNA detections and routine profile tests for HBV infection. The individuals with negative repeated ELISA but positive DNA detection were followed-up after 6 months of primary examinations. Results 0.12 % cases presented positive NAT although they were negative when tested by repeated ELISA. Among them,22 cases were OBI infections and 4 fell in window phase of HBV infection. All of the OBI donors were characterized by positive HBcAb（100%）,followed by HBeAg （63.6%）.All of the 31 samples exhibited single or combined positivity of routine profile tests for HBsAg,HBsAb,HBeAb,or HbcAb. Conclusion DNA detection may cover the shortage of ELISA,shorten the window phase,and avoid misdiagnosis so as to reduce the risk at transmission of infectious diseases.

Key words: Hepatitis B virus surface antigen, Nucleic acid detection technology, ELISA, Latent hepatitis B virus infection