Which result indicates that a person has chronic Hepatitis B?

A positive HBsAg result is a definitive marker for chronic Hepatitis B infection. HBsAg, or Hepatitis B surface antigen, is a protein on the virus's surface that is present in the blood when someone is infected with the Hepatitis B virus. In chronic Hepatitis B, HBsAg remains positive for more than six months, indicating that the virus is chronically active in the body.

In contrast, negative HBsAg suggests that the person is not currently infected with the Hepatitis B virus. A positive Anti-HBs result signifies that the individual has either cleared the infection or has been successfully vaccinated, which points away from a chronic infection. A negative Anti-HBc would indicate that there is no prior exposure to the virus, which further confirms that chronic Hepatitis B is not present. Therefore, the presence of HBsAg is crucial for diagnosing chronic Hepatitis B.