Hepatitis B tests

What the test is

All adults should be screened at least once, and everyone should be tested in each pregnancy.

What it measures

• Surface antigen (HBsAg): current infection
• Surface antibody (anti-HBs): protection from vaccine or past infection
• Core antibody (anti-HBc): past or current infection

Why it's done

• Routine screening
• Pregnancy
• Abnormal liver tests
• Before treatments that weaken the immune system
• Checking vaccine protection

Getting ready and what happens

• No preparation is needed.

How the test is done

• A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.

What the results mean

HBsAg positive

You have hepatitis B. More tests check how active it is. Treatment and liver monitoring may be needed, and close contacts should be vaccinated.

Only anti-HBs positive

You're protected, usually from the vaccine.

All negative

You're not protected; the vaccine is recommended.

Questions to ask your provider

• What do my results mean for me?
• Do I need to repeat this test or have other tests?
• Should my family be tested or vaccinated?
• Do I need treatment or regular liver checks?

Risks

A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.

Related conditions

• Hepatitis B
• Hepatitis or liver inflammation
• Cirrhosis (liver scarring)
• Liver cancer (needs checking)

Related tests

• Liver function tests
• Hepatitis C test
• HIV test