What does a positive test for IgM anti-HBc indicate about a staff member?

A positive test for IgM anti-HBc (immunoglobulin M antibody to the hepatitis B core antigen) indicates that the individual has recently been infected with the hepatitis B virus. This finding suggests that the body is in the early stages of responding to the virus, typically within the first few months following the infection.

IgM anti-HBc is often one of the earliest serological markers to appear during acute hepatitis B infection and remains positive for a limited time. Its presence is a key indicator for health professionals to identify individuals who may currently be experiencing an active infection, distinguishing them from those who have cleared the virus or have been vaccinated against it.

Understanding this relates to other options: being a chronic carrier implies a persistent infection that does not align with the timeline indicated by IgM presence, immunity suggests cleared or vaccinated status that would not present with IgM, and exposure without infection would typically result in different serological markers rather than a positive IgM anti-HBc.