What indicates acute infection in Hepatitis B?

Acute infection in Hepatitis B is indicated primarily by the presence of Hepatitis B surface antigen (HBsAg) and antibody to Hepatitis B core antigen (Anti-HBc). In the context of identifying an acute infection specifically, Anti-HBc is particularly significant because it indicates recent or ongoing infection with the virus, as this antibody appears shortly after exposure to the virus and persists for life.

When determining acute Hepatitis B infection, HBsAg is typically the first marker to rise in the blood, indicating active replication of the virus. However, Anti-HBc is essential for evaluation as it signifies the body's immune response to the core antigens of the virus and correlates with the acute phase of infection. Therefore, the presence of IgM type of Anti-HBc, commonly tested in this context, affirms that the infection is recent.

While other markers like Anti-HBs indicate recovery or vaccination and Anti-HCV relates to Hepatitis C, they do not directly denote an acute Hepatitis B infection. Thus, the presence of Anti-HBc specifically supports the diagnosis in the acute phase of a Hepatitis B infection.