In which condition would you expect to find a positive HBsAg?

A positive HBsAg (Hepatitis B surface Antigen) indicates the presence of an active Hepatitis B virus infection. This antigen is a protein on the surface of the virus, and its detection in the blood signifies that the virus is replicating and the individual is contagious.

In the context of acute or chronic hepatitis B infection, the presence of HBsAg is typically the first marker that appears in the bloodstream after infection. During acute infections, HBsAg can be detected within 1 to 10 weeks after exposure to the virus, peaking around 6 to 8 weeks. If the infection becomes chronic, HBsAg can remain positive for many years, which is an indicator of ongoing viral replication and a potential risk for liver damage and complications.

In contrast, other conditions listed do not typically present with positive HBsAg. Chronic hepatitis C infection would show antibodies to hepatitis C virus (anti-HCV) instead. Hepatocellular carcinoma may develop due to chronic hepatitis B infection but does not inherently indicate the presence of HBsAg unless the underlying viral infection is present. Nonalcoholic fatty liver disease is characterized by hepatic steatosis without significant inflammation or liver cell necrosis and does not involve the hepatitis B