Which marker indicates a current or previously infected individual with Hepatitis B?

In assessing Hepatitis B infection, the presence of specific serological markers is crucial for classifying the infection status. The marker that indicates a current or previous infection with Hepatitis B is HBsAg, which stands for Hepatitis B surface antigen.

When HBsAg is detected in the blood, it signifies that the virus is currently present, indicating an active Hepatitis B infection. This could be an acute infection, which develops soon after exposure to the virus, or a chronic infection if the surface antigen remains positive for six months or longer.

The other markers serve different purposes. For instance, Anti-HBs refers to antibodies formed in response to the Hepatitis B surface antigen and indicates recovery and immunity, either from natural infection or vaccination.

IgM Anti-HBc (Immunoglobulin M antibody to Hepatitis B core antigen) indicates a recent infection, but it does not tell us about past infections.

HBeAg is a marker indicating active viral replication and correlates with higher infectiousness.

Thus, the marker indicating a current or previously infected individual with Hepatitis B is accurately represented by HBsAg.