Occult Hepatitis B Virus Infection Among Blood Donors of North India

BackgroundHepatitis B virus (HBV) testing of blood donors in India is focused on the presence of HBsAg. However, the absence of HBsAg in the blood of the healthy individual may not be sufficient to ensure lack of circulating HBV.AimThe aim of this study is to estimate the prevalence of anti HBc and anti HBs pattern in anti HBc reactive but HBsAg negative blood donors.Material and Methods6134 Blood donor samples were tested prospectively from 16th April to 7th July, 2007 for HbsAg and anti HBc (IgM + IgG) antibodies using BIORAD MONOLISA HbsAg ULTRA and BIO-RAD MONOLISA anti-HBc PLUS test kits. All the samples, which were negative for HbsAg but reactive for anti HBc, were tested for anti-HBs antibodies Using BIO-RAD MONOLISA ANTI HBs 3.0 test kits.ResultsOut of 6134 donor samples tested, 63 samples were HbsAg positive (1.02 %) and 499 samples (8.13%) showed anti HBc reactivity but HbsAg negative.195 (39.07%) out of 499 anti HBc positive samples showed levels of anti HBs above 15 IU/ml and 304 (60.92 %) showed levels of anti HBs below 15 IU/mL. The samples showing values above 15 IU/mL are considered positive and samples below 15 IU/mL are considered negative as per BIO-RAD MONOLISA anti HBs 3.0 instruction manual.ConclusionThe data indicates that high percentage of blood donors (60.92%) were anti-HBc reactive and have low levels of preventive anti HBs antibodies. Accordingly all blood donor samples should be tested routinely for anti HBc and if the sera are reactive, regardless of anti-HBs titer, the blood should be discarded. Further testing for HBV-DNA is appropriate to follow up the blood donor for HBV infection.