The Hepatitis B Core Antibody IgM (Anti-HBc-IgM) test is a blood test that detects the presence of IgM antibodies against the Hepatitis B virus core antigen. The test is used to diagnose acute or recent Hepatitis B infection. The IgM antibodies are produced by the body in response to the virus and can be detected within four to six weeks of infection. The test is usually ordered when a person shows symptoms of Hepatitis B, such as jaundice, fatigue, and abdominal pain. A positive Anti-HBc-IgM test result indicates that the person has an acute or recent Hepatitis B infection, while a negative result suggests that they have not been recently infected. However, a positive result does not necessarily indicate active infection, as the antibodies can persist in the body for several months after the infection has resolved. The Anti-HBc-IgM test is an important tool in the diagnosis and management of Hepatitis B, and it is often performed alongside other liver function tests and Hepatitis B surface antigen tests.