To determine the endemicity of hepatitis B, what should be measured -

Ans. is 'a' i.e., HBsAg o HBsAg testing is widely used as a marker of HBV infection in epidemiological surveys.Serological markers for HBVo Serological markers for HBV infection areHBs Ag (surface antigen or Australia antigen) : It is the first marker which appears in the serum. It is the epidemiological marker for HBV infection.HBc Ag (core antigen) : It is not demonstrable in serum because it is enclosed by HBsAg coat.HBe Ag (envelope antigen) : It is marker of active replication and high infectivity. It is qualitative marker of replication. HBs Ag carrier mothers who are HBe Ag positive almost invariably (> 90%) transmit hepatitis B infection to their offspring, where as HBs Ag carrier mothers with anti HBe rarely (10 to 15%) infect their offspring.Anti-HBc Ag : It is the first antibody appears in serum. IgM anti-HBc Ag is a marker of acute or recent infection. IgG anti-HBc Ag indicates remote infection.Anti-HBs Ag : It is protective antibody. It is the only serological marker present after vaccination. After an infection, its presence indicates recovery and end of period of communicability.Anti-HBe Ag : Its presence indicate stopage of replication and tow infectivity.HBV DMA : It is quantitative marker of HBV replication.