- Fasting and prep
- No fasting needed. Follow the instructions on your lab order.
- Turnaround
- Usually 1 to 3 days. Labs confirm a positive result, which can add time.
- Also called
- hbsag, hep b surface antigen, hepatitis b test, hepatitis b screening
What it measures
HBsAg appears in the blood within weeks of infection. In most adults the body clears the virus and HBsAg disappears within about 6 months. If it lasts longer than 6 months, the infection is called chronic. For full screening, the CDC recommends a three-part panel: HBsAg, surface antibody (anti-HBs), and core antibody (anti-HBc), which together show infection, immunity, or past exposure.
Who should consider it
- All adults at least once, per CDC
- People who are pregnant, during each pregnancy
- People born in regions where hepatitis B is common
- Anyone with a partner or household member who has hepatitis B
- People who inject drugs, people living with HIV, and anyone with abnormal liver tests
How to read your result
- Negative means no current hepatitis B infection. It does not tell you whether you are immune. The surface antibody test answers that.
- Positive means a current infection. A repeat test after 6 months shows whether it cleared or became chronic.
- Very recent exposure can test negative, so retest if you had a known exposure.
- Vaccines contain a version of the surface antigen, and a test drawn within a few weeks of a dose can rarely turn positive briefly.
Reference ranges differ between labs. Use the range printed on your own report.
What to do next
If your HBsAg is positive, see a clinician for follow-up tests, including viral load and liver checks. Many people with chronic hepatitis B need monitoring, and some need antiviral medicine that protects the liver. Household members and sex partners should get tested and vaccinated if they are not immune.
Where to order Hepatitis B surface antigen
These sellers include an independent physician order. You pay online and visit a partner lab. Availability, price, and lab network vary, so confirm at checkout.
Private MD Labs
Online lab seller- Order
- Every order reviewed by a physician. Says you pay $1 to start and the rest after results.
- Results
- Secure online portal with plain-English explanations. Says many results arrive overnight.
HealthLabs
Online lab seller- Order
- Online or by phone. No doctor referral or insurance needed.
- Results
- Secure HealthLabs account. Says 1 to 3 business days.
Walk-In Lab
Online lab seller- Order
- Online, no insurance or doctor order needed. Shows a $6 physician fee per order on popular tests.
- Results
- Online account. Turnaround not stated on its homepage.
Quest Health
Lab-run- Order
- Buy online and book a Quest appointment. An independent provider is involved.
- Results
- Online as soon as ready, with an email alert. Provider discussion included at no extra cost.
Seller details come from each seller's own site and can change. Confirm price, lab location, and state availability at checkout.
Ordering several tests? Plan them together · Filter all sellers
Questions people ask
What does a positive hepatitis B surface antigen mean?
It means the virus is in your blood now. A clinician will run more tests to see whether the infection is new or chronic and whether it needs treatment.
Does a negative HBsAg mean I am protected?
No. It only means you have no current infection. A hepatitis B surface antibody test shows whether you are immune from vaccination or past infection.
Can hepatitis B be cured?
Most adults clear a new infection on their own. Chronic hepatitis B can be controlled with medicine, though a full cure is uncommon. A vaccine prevents it.
Can I order an HBsAg test without a doctor?
Yes. Online sellers offer it alone or in hepatitis panels, with a physician order and a blood draw at a partner lab.
Related tests
- Hepatitis B immunity testMeasures antibodies that protect you from hepatitis B.
- Hepatitis C testScreens for hepatitis C and checks whether the virus is active.
- Hepatic function panelALT, AST, ALP, bilirubin, and protein to check liver health.
- STD test panelChecks for several common sexually transmitted infections at once.
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