Hepatitis B test results
A hepatitis B screen is often 3 blood tests read together: the surface antigen (HBsAg), the surface antibody (anti-HBs) and the core antibody (anti-HBc). The pattern shows whether you are protected by the vaccine, recovered from a past infection, have an infection now, or are not protected. Labs report results in different ways, so ask your provider what yours mean; your doctor decides the next step. (CDC, 2023) (MedlinePlus, 2025)
The 3 tests
- HBsAg (hepatitis B surface antigen): part of the virus itself. Positive means a hepatitis B infection, acute or chronic, except that it can be briefly positive shortly after a vaccine dose. (CDC, 2023) (MedlinePlus, 2025)
- Anti-HBs (surface antibody): made after a hepatitis B infection or after the vaccine. After a completed vaccine series, 10 mIU/mL or more means immunity. Levels can fade over the years in people who did respond to the vaccine. (CDC, 2023) (MedlinePlus, 2025)
- Anti-HBc (total core antibody): made only after an infection, past or current, and usually present for life. The vaccine does not cause it. (CDC, 2023) (MedlinePlus, 2025)
The CDC recommends ordering all 3 together (a "triple panel") for a first screen, because together they show who has an infection, who recovered, who is protected and who needs the vaccine. (CDC, 2023) The USPSTF screening test is HBsAg, with a confirmatory test if it is reactive. (USPSTF, 2020)
What each result pattern means
These are the patterns in the CDC's 2023 interpretation table, with the next step it lists. (CDC, 2023)
| HBsAg | Anti-HBs | Anti-HBc | What it means | Usual next step |
|---|---|---|---|---|
| Negative | Positive | Negative | Immune from the vaccine | Reassured if the vaccine series was completed; if it was only partly given, the series is completed (CDC, 2023) |
| Negative | Positive | Positive | Immune after a past infection that went away (resolved) | Told about the risk that the infection can reactivate (CDC, 2023) |
| Positive | Negative | Positive | Current infection: acute (new) or chronic (long-lasting) | Linked to hepatitis B care (CDC, 2023) |
| Negative | Negative | Negative | Never infected and not protected (susceptible) | Offered the hepatitis B vaccine (CDC, 2023) |
| Negative | Negative | Positive | Unclear: "isolated core antibody" | Depends on the cause; more testing (CDC, 2023) |
- Acute or chronic? A separate IgM anti-HBc test is positive in a new (acute) infection and usually negative in a chronic one; it is ordered only when a new infection is a concern. Chronic infection means HBsAg has been present for at least 6 months. (CDC, 2023) NIDDK says chronic infection develops in about 5% of infected adults, but in about 90% of infants infected before age 1. (NIDDK, 2024)
- Isolated core antibody: the CDC lists several possible causes: a past infection whose anti-HBs has faded, a hidden (occult) infection, antibody passed from a parent to a young infant, a false positive, or a virus strain the HBsAg test does not detect. (CDC, 2023)
- A recent exposure: MedlinePlus says a negative result means you probably do not have hepatitis, but if you know you were exposed you may need to test again later. (MedlinePlus, 2025)
Why an HBV DNA test may follow
HBV DNA measures the amount of virus in the blood (viral load). After a hepatitis B infection is found, the CDC says HBV DNA, HBeAg and anti-HBe tests show how actively the virus is copying itself and how infectious it is, and help guide care. Follow-up testing for people with hepatitis B also includes liver blood tests and tests for hepatitis C, hepatitis D and HIV. (CDC, 2023) Your doctor decides which tests you need. This page does not give treatment advice. See also after an abnormal screening result.
Who should be tested: two views
- USPSTF (2020): screen adolescents and adults at increased risk, including people who were vaccinated before being screened, and screen again from time to time while the risk continues (grade B). (USPSTF, 2020) Increased risk includes being born in a country where 2% or more of people have hepatitis B, injection drug use, men who have sex with men, people with HIV, and sex partners and household contacts of people with hepatitis B. (USPSTF, 2020)
- CDC (2023): screen all adults 18 and older at least once in their lifetime with the triple panel, and test people with ongoing risk from time to time. (CDC, 2023)
- Pregnancy: both call for testing in every pregnancy, regardless of vaccination or past results: the USPSTF an HBsAg test at the first prenatal visit (grade A, 2019), the CDC preferably in the first trimester. (USPSTF, 2019) (CDC, 2023)
Full details: hepatitis B screening. Ask your doctor which applies to you.
Cost and coverage
Medicare Part B covers hepatitis B screening when your provider orders it and you are at high risk or pregnant. It is covered once a year if you stay at high risk and do not get the vaccine, and in pregnancy at the first prenatal visit and at delivery if you have new or continued risk. You pay nothing if your provider accepts assignment. (Medicare.gov) For private plans, see preventive screenings covered by insurance.
Questions people ask
What does a positive hepatitis B surface antigen (HBsAg) mean?
The CDC says a positive HBsAg shows a hepatitis B infection, either acute or chronic. One exception: it can be briefly positive shortly after a dose of hepatitis B vaccine. Chronic infection is defined as HBsAg present for at least 6 months. (CDC, 2023)
What does a positive anti-HBs mean?
Anti-HBs is the antibody that protects you. With a negative anti-HBc, it means immunity from the vaccine; the CDC uses a level of 10 mIU/mL or more after a completed vaccine series. With a positive anti-HBc, it means you recovered from a past infection. (CDC, 2023)
What does a positive hepatitis B core antibody (anti-HBc) mean?
Anti-HBc forms in every hepatitis B infection, past or current, and usually stays for life. The vaccine does not cause it. Whether the infection is current depends on the HBsAg result: positive means current infection, negative with a positive anti-HBs means a past infection that went away. (CDC, 2023)
Do I need to fast or prepare for a hepatitis B test?
No. MedlinePlus says no special preparation is needed. It is a blood draw, and there is very little risk beyond slight pain or bruising. (MedlinePlus, 2025)
Does Medicare cover hepatitis B screening?
Medicare Part B covers it when your provider orders it and you are at high risk or pregnant. If you are at continued high risk and do not get the vaccine, it is covered once a year. You pay nothing if your provider accepts assignment. (Medicare.gov)