What does the hepatitis B surface antigen test mean?

A positive result may reflect a recent infection or an infection that has lasted longer; additional testing helps distinguish these situations. A negative result means the antigen was not detected in the sample, but it does not automatically describe vaccination or immunity. Hepatitis B can cause no symptoms, while fatigue or dark urine may occur in some people. See [Hepatitis B](/conditions/hepatitis-b/), [Fatigue](/symptoms/fatigue/) and [Dark Urine](/symptoms/dark-urine/).

Take the report to the clinician who ordered it rather than interpreting one line in isolation. They may request further hepatitis B markers, repeat testing or a [Liver Function Test](/treatments/diagnostics-and-screening/liver-function-test/). Until you have advice, do not share blood-contaminated personal items, and tell relevant healthcare professionals about a positive result. People who may have been exposed can ask about [Hepatitis B Vaccination](/treatments/preventive-care-and-vaccination/hepatitis-b-vaccination/).

Get urgent help for confusion, severe vomiting, yellow skin or eyes, unusual bleeding or rapidly increasing abdominal swelling. Arrange prompt medical review for new dark urine, pale stools or worsening tiredness, particularly if HBsAg was detected.

What do my HBsAg and other hepatitis B markers show together? Do I need repeat or confirmatory testing? Should my liver function be checked? Could close contacts need testing or vaccination? What precautions should I take while the result is being clarified?