The Relationship between HBSAG and HBV DNA in HBV-Infected Blood Donors

Hepatitis B virus (HBV) screening among blood donors in Iran is focused on the presence of hepatitis B surface antigen (HBsAg). The absence of HBsAg in the healthy blood donors may not be sufficient to ensure lack of circulating HBV. However, nucleic acid testing (NAT) has been introduced in most developed countries for the screening of infectious agents in pooled plasma and individual donation. Understanding the relationship between HBsAg and HBV deoxyribonucleic acid (DNA) concentrations in HBV infected blood donor is an important in assessing the roles that HBsAg assays and HBV NAT will play in the future of blood screening. The aim of this study was to show the results about screening for HBV in blood donors and to remark the relationship between HBV DNA and HBsAg. HBsAg testing for 58400 healthy volunteer donors was conducted using HBsAg Enzyme Immunoassay kit (Monolisa, Bio-RAD, France) during Sep 2004 to Feb 2005. All specimens repeatedly reactivate for HBsAg were tested and confirmed by a neutralization assay (HBsAg confirmatory assay Monolisa, Bio-RAD, France). Samples from HBsAg positive donations were tested using semi-nested PCR to detect HBV DNA. A total of 350 (0.6%) of 58400 blood donors were HBsAg positive. HBV DNA was detected among 90 of 350(25.7%) of the HBsAg positive blood donors. HBV DNA was not found among 260(74.2%) of the positive HBs in HBsAg positive blood donations can be extremely low. About 74.2 percent of donations would remain undetected by single donor NAT. These results indicate that HBsAg positive units from donors in the chronic stage of infection or late infection may contain very low or intermittently detectable DNA levels that single sample NAT would miss.