Which hepatitis B marker is the best indicator of early acute infection?

HBsAg (Hepatitis B surface antigen) is indeed the best indicator of early acute infection with the hepatitis B virus. This marker appears in the blood shortly after infection, as the virus begins to replicate. The presence of HBsAg indicates that the virus is actively present in the bloodstream, indicating that an infection is currently occurring.

It is important to note the role of the other markers as well. HBeAg is a marker of viral replication and can indicate high levels of virus in the blood, but it typically appears after HBsAg. Anti-HBc (antibody to hepatitis B core antigen) can suggest past or resolving infection but is not specific to the early stages of infection. Anti-HBs (antibody to hepatitis B surface antigen) is associated with recovery or vaccination, indicating that the person is no longer infected, thus it is not relevant in diagnosing early acute infection. The timing of these markers helps in understanding the progression of the infection and HBsAg serves as the initial alarm for acute hepatitis B.