Hepatitis B virus blood screening: impact of nucleic amplification technology testing implementation on identifying hepatitis B surface antigen non-reactive window period and chronic infections

Despite improvements in hepatitis B surface antigen (HBsAg) test sensitivity, post-transfusion hepatitis B virus (HBV) infection still occurs because HBsAg is undetectable during the early window phase (WP) of the infection, in the convalescence core window phase of the infection, or in serologically silent chronic hepatitis or in mutant forms of HBV. HBV-DNA screening using high sensitivity nucleic amplification technology (NAT) assays has recently been introduced to reduce the residual risk of transmission of HBV by transfusion of blood components.