Continued from Part - I & II .......... In transfusion medicine safety of blood products is a major concern. The hepatitis B virus getting transmitted through blood transfusion is far more than the hepatitis C virus it is around 1:60000 vs 1:103000 (Schreiber, Busch, Kleinman, Korelitz. 1996). This is despite of availability of assay for screening quite sensitive to detect hepatitis B virus surface antigen or HBsAg. It is very common incidence of hepatitis B infection in post-transfusion cases (Saraswat, Banerjee, Chaudhury, Mahant,Khandekar, Gupta, et al.1996). Common explanations what offered for incorrect negative findings or results with the common assays are due to circulation of viral protein in low level. This can escape detection and screening of HBsAg mutant`s infection by assays in blood donors. Obviously this cause hazards in post blood transfusion (Jongerius, Wester, Cuypers, van Oostendorp,Lelie, van der Poel, et al.1998). Besides this other reason is cited ...