Objective Some blood donors were negative for the surface antigen but positive for the core antibody,leading to acute hepatitis.This study was to determine the seroprevalence of the hepatitis B core antibody in voluntary blood donors.Methods A total of 9100 donor samples were screened for hepatitis B surface antigen and Hepatitis B core antibody with enzyme-linked immunosorbent assay(ELISA).The samples which were positive for the core antibody were subjected to real-time polymerase chain reaction (PCR) for the hepatitis B DNA detection.Results Among the 9100 donors,911 (10.01％) donors were positive for the core antibody.The hepatitis B surface antigen was positive in 199 (2.19％) donors.Among the 911 donors who were positive for the core antibody,820 (90.01％) donors were negative for the HB-sAg,and 35 donors were positive for hepatitis B DNA.Conclusions If a routine screening of the sera for the core antibody is not done,the HBV DNA viraemia may not be identified.The absence of the surface antigen in the blood of apparently healthy individuals may not be sufficient to ensure the lack of the circulating virus.It is necessary to attach importance to the blood donors screening HBsAg-negative population further serological testing,suspicious specimens should detect HBV DNA.