Hepatitis B Surface Antigen Test: What It Shows and What It Does Not
Quick answer: The hepatitis B surface antigen test, or HBsAg, looks for a protein on the hepatitis B virus. A positive result means the virus is present in your blood. It is used to screen for current hepatitis B infection.
About this test
HBsAg is a protein found on the surface of the hepatitis B virus. It appears in the blood during acute infection and stays present in chronic infection.
Why is it ordered?
- Screening for hepatitis B infection.
- A new partner or possible exposure.
- Pregnancy care and before some treatments.
What results may show
- A positive result means current hepatitis B infection, acute or chronic, and needs follow up with a provider.
- A negative result suggests no current infection.
What this test may not show
- It does not show whether you are immune or vaccinated. A different test does that.
- It does not show past infection that has cleared.
- A very recent exposure may not be detected yet.
- It does not show liver damage.
How to prepare
- No special preparation is needed.
Where you can get this test
| Option | Price | Includes |
|---|---|---|
| STD Screening Panel, Comprehensive | $199 | Chlamydia, gonorrhea, trichomoniasis, syphilis, HIV 1 and 2, hepatitis B surface antigen, hepatitis C antibody |
A doctor’s visit is not required to order. Order online, then visit our Buffalo Grove or Lake Zurich location for the sample. Review results with your own healthcare provider.
Related tests
Frequently asked questions
Does a negative result mean I am immune?
Not necessarily. Immunity is checked with a different antibody test.
What does a positive result mean?
You have the virus now and need follow up with a provider.
Is there a vaccine?
Yes. Talk with your provider about hepatitis B vaccination.
Sources
Medically reviewed by Rodion Levin, FNP-C, Founder and Medical Director. This page is for general education. It does not diagnose a condition or replace advice from your healthcare provider.
