Which statement about anti-HBC is true regarding hepatitis B?

Anti-HBc, or antibody to hepatitis B core antigen, is a marker that indicates a person's prior exposure to the hepatitis B virus. When someone has anti-HBc present, it signifies that the individual has been infected with the virus at some point in their life, which could either be in an acute or chronic phase of hepatitis B infection.

The presence of anti-HBc can indicate recovery from an infection, but it does not necessarily show that a person is immune or vaccinated. This differs from other markers such as anti-HBs, which indicates immunity and can confirm successful vaccination against hepatitis B, or HBsAg, which indicates active infection.

Thus, the correct statement regarding anti-HBc is that it shows past infection. This marker is critical in the serological assessment of hepatitis B to understand an individual's exposure history and potential immunity.