Hepatitis antigen and antibody tests: what the results mean

An antigen is a substance from the virus. Finding one can suggest that viral material is present at the time of testing. An antibody is made by the immune system after exposure, infection, or vaccination, depending on the antibody being measured. A positive antibody result does not by itself prove that infection is active or that treatment is needed.

Timing matters. Early testing may not detect an antibody yet, while an antibody can remain after an earlier infection has resolved. Clinicians may compare several markers, symptoms, and liver blood tests to form a clearer picture. Hepatitis A can cause nausea, loss of appetite, feeling generally unwell, or dark urine.

Take the complete report to the clinician who ordered it, including the exact marker names and reference ranges. Do not interpret a single reactive or non-reactive line in isolation. Your clinician may recommend repeat testing, a Liver Function Test, or other checks based on your exposure history and symptoms. Until the result is explained, avoid sharing personal items that may carry blood and ask about precautions relevant to your household.

Arrange prompt medical advice for yellowing of the skin or eyes, worsening dark urine, repeated vomiting, severe abdominal pain, confusion, or unusual drowsiness. Seek urgent help if you cannot keep fluids down or feel faint. Symptoms do not identify the cause on their own, so testing and examination remain important.

Which antigen or antibody was tested, and is the pattern consistent with current infection, past exposure, or vaccination? Do I need a Liver Function Test or repeat sample? Should household or sexual contacts discuss Hepatitis A Vaccination?