Which test result indicates an acute Hepatitis B infection within the last six months?

In the context of diagnosing an acute Hepatitis B infection, the presence of IgM antibodies to the Hepatitis B core antigen (IgM anti-HBc) is specifically indicative of a recent infection, typically within the last six months. The detection of IgM anti-HBc suggests that the body is responding to the active replication of the virus, which is characteristic of acute hepatitis.

HBsAg (Hepatitis B surface antigen) signifies that the virus is currently present in the blood, but it does not differentiate between acute and chronic infections. Anti-HBs (antibodies to Hepatitis B surface antigen) indicates past infection or vaccination, as it suggests that the immune system has responded to the virus or the vaccine, which is not relevant for identifying an acute infection. The presence of anti-HBc (total) could indicate either an acute or chronic infection and doesn't specify the timing as IgM anti-HBc does. Thus, IgM anti-HBc is the most reliable test result for confirming an acute Hepatitis B infection within the specified timeframe.