**Anti-Hepatitis A Virus (Anti-HAV) IgG** is a specific antibody produced by the immune system in response to the Hepatitis A virus or vaccination. Its presence in a blood test signifies long-term immunity against the virus, meaning the individual is protected from future infections.
Unlike IgM antibodies, which indicate an active or recent acute infection, IgG antibodies develop later during the recovery phase or following successful immunization and persist for life. Identifying Anti-HAV IgG is clinically crucial to confirm previous exposure, verify vaccine efficacy, and determine if a person requires vaccination before traveling to endemic areas.

**Anti-Hepatitis A Virus (Anti-HAV) IgM** is a crucial diagnostic antibody produced by the body during an acute or recent infection with the Hepatitis A virus. Its presence in a patient's blood sample serves as the primary marker for diagnosing sudden-onset, active Hepatitis A.
Unlike the IgG antibody, which represents long-term immunity, IgM antibodies appear early after viral exposure—typically coinciding with the onset of symptoms like jaundice, fatigue, and abdominal pain. Anti-HAV IgM levels remain elevated for roughly three to six months, making this test essential for differentiating a current, active illness from past exposure.

**Anti-Hepatitis B Core Antibody (Anti-HBc) IgM** is a vital serological marker that indicates a clinical diagnosis of acute or recent Hepatitis B virus (HBV) infection. It is the earliest antibody to appear during an acute outbreak, often becoming detectable in the blood shortly after symptoms surface.
This specific IgM antibody is especially critical during the "window period"—the clinical phase when Hepatitis B Surface Antigen (HBsAg) has cleared, but Hepatitis B Surface Antibody (HBsAb) is not yet detectable. Its presence confirms an active, sharp immune response to a new infection rather than a chronic condition.