What indicates ongoing infection in Hepatitis B?

Ongoing infection in Hepatitis B is indicated by the presence of HBsAg (Hepatitis B surface antigen) in the blood. HBsAg is a protein on the surface of the Hepatitis B virus; its presence signifies that the virus is currently replicating in the body, which is characteristic of an active infection.

In contrast, Anti-HBs (antibody to the hepatitis B surface antigen) indicates recovery and immunity from hepatitis B; thus, it does not suggest ongoing infection. Anti-HBc (antibody to the hepatitis B core antigen) can indicate a current or past infection, but it does not differentiate between the two states. Anti-HCV is related to Hepatitis C and is not pertinent to the diagnosis of Hepatitis B infection. Therefore, the presence of HBsAg is crucial for diagnosing an active Hepatitis B infection.