What is the hepatitis B core antibody test?

A blood sample is checked for antibodies directed at the core of the hepatitis B virus. The test can help clinicians work out whether someone may have encountered the virus. It does not, on its own, distinguish a current infection from a past infection, confirm immunity, or show how much virus is present. Results are considered together with surface antigen, surface antibody, symptoms and exposure history.

Usually, the key step is to review the complete test panel with the requesting clinician. Depending on the pattern, they may repeat blood tests, request a viral test, or check liver inflammation with a [Liver Function Test](/treatments/diagnostics-and-screening/liver-function-test/). If you have no evidence of protection, ask about [Hepatitis B Vaccination](/treatments/preventive-care-and-vaccination/hepatitis-b-vaccination/). Keep a note of possible exposure dates and any earlier results.

Contact the clinician who ordered the test if the result is positive, unclear, or unexpected, particularly after a recent exposure. Seek urgent care for confusion, severe vomiting, severe abdominal pain, or yellowing that is rapidly worsening. [Fatigue](/symptoms/fatigue/) and [Dark Urine](/symptoms/dark-urine/) deserve assessment when they occur with other liver-related symptoms. Read more about [Hepatitis B](/conditions/hepatitis-b/).

Ask what your full panel means, whether additional testing is needed, whether you are protected, and whether anyone close to you should be tested or vaccinated.