Synonyms: Antibody to Hepatitis B Surface Antigen; Anti-HBs; HBsAb; Hepatitis Bs Antibody

Why It Is Done

Identify the type of hepatitis virus causing the infection.
Screen people who have an increased risk of getting or spreading a viral hepatitis infection.
Screen blood donors and donor organs to prevent the spread of hepatitis.
Find out if a person has developed antibodies after receiving vaccinations for hepatitis B.
Check abnormal liver function tests.

Test Overview

Hepatitis B surface antibody (HBsAb) is one of the most common tests for HBV. Usually this antibody appears about 4 weeks after HBsAg disappears and means that the infection is at the end of its active stage and you cannot pass the virus to others (you are no longer contagious). This antibody also protects you from getting HBV again in the future. The test is done to determine the need for vaccination; the antibody will be present after receiving the HBV vaccine series, showing that you have protection (immunity) from the virus. Occasionally your test may show that you have both the HBsAb and HBsAg antibodies; in this case, you are still contagious.

How To Prepare

No special preparation is necessary.

WARNING: If you test positive for Hep B, the testing lab (NOT HTD) may be required by law to report your result to one or more government health agencies.