What should you know about a hepatitis B lab test?

Testing commonly looks for hepatitis B surface antigen, surface antibody and core antibody. Their combination helps a clinician distinguish current infection from previous exposure or protection after vaccination. A positive surface antigen can indicate current infection and may need repeat testing or additional tests. A surface antibody can indicate immunity, while a core antibody may show previous exposure. One result should not be read in isolation.

The clinician may also request a liver function test to assess how the liver is responding. Some people have no symptoms; others notice fatigue or dark urine. These symptoms can have several causes and do not establish hepatitis B by themselves.

Ask the testing service to explain each marker, whether the sample needs repeating, and whether further blood tests or liver assessment are needed. Until the result is clarified, do not share razors or toothbrushes, and discuss safer sex and household precautions with a clinician. Avoid starting supplements or stopping prescribed medicines without advice, because the liver processes many medicines.

If current infection is confirmed, arrange follow-up with a qualified clinician. Partners and household contacts can ask whether they need testing or hepatitis B vaccination. Keep a copy of the result and the date of the sample for future appointments.

Contact a clinician promptly if a result suggests current infection, if you develop yellowing of the eyes or skin, worsening dark urine, repeated vomiting, unusual sleepiness, confusion, or severe abdominal swelling. Seek emergency care for confusion, collapse, vomiting blood, or severe breathing difficulty. These signs need assessment regardless of the hepatitis B result.

Ask: Which hepatitis B markers were tested? Does this pattern suggest current infection, past exposure, or vaccine protection? Do I need a repeat sample, liver function test, or specialist review? Should my household or sexual contacts be tested or vaccinated?