High Prevalence of HBV Infectivity in Blood Donors Detected by the Dot Blot Hybridisation Assay

Hepatitis B virus (HBV) continues to be a significant cause for post‐transfusion hepatitis in India, in spite of the introduction of compulsory hepatitis B surface antigen (HBsAg) screening. To understand the true HBV‐infective pool in the blood donor population, HBV DNA was detected by a ³²P‐labelled dot blot hybridisation assay in 605 donor units that were negative for HBsAg by a third‐generation Elisa. Serum alanine aminotransferase (ALT) was estimated in all these samples and correlated with DNA positivity. The frequency of HBV DNA positivity in HBsAg‐negative units was very high (9.91%) and correlated well with the elevation in ALT (p<0.00005). However, the frequency of elevated ALT was high (11.9%), using the locally determined upper limit of normal, and half of the DNA‐positive samples had a normal ALT. Thus, ALT is a poor surrogate marker for HBV infectivity and efforts should be made to apply DNA detection systems in blood banks.