Dr. Vaccines
Hepatitis B Serology Test
Three markers that distinguish current infection, past infection and vaccine-induced immunity, results that are easy to misread.
Hepatitis B testing confuses people more than any other serology, because a single test in isolation rarely answers the question you actually have. Three markers are usually measured together, and it is the combination that carries the meaning.
HBsAg indicates current infection. Anti-HBs indicates immunity. Anti-HBc indicates past exposure to the actual virus, and crucially it is negative in people whose immunity came from vaccination. That last marker is what separates "vaccinated" from "infected and recovered".
At a glance
The three markers and what each one tells you.
| Vaccine or test | Status | Schedule | Detail |
|---|---|---|---|
| HBsAg (surface antigen) | Recommended | Part of the standard panel | Positive means the virus is currently present: you have hepatitis B infection, acute or chronic, and you are potentially infectious to others. This is the marker that changes management most. |
| Anti-HBs (surface antibody) | Recommended | Part of the standard panel | The protective antibody. A level of 10 mIU/mL or above indicates immunity, whether from vaccination or from clearing a past infection. This is the number checked after a vaccination course to confirm you responded. |
| Anti-HBc (core antibody) | Recommended | Part of the standard panel | Indicates exposure to the real virus at some point. It is never produced by the vaccine, which is why it distinguishes vaccine-induced immunity from immunity acquired by infection and recovery. |
| Hepatitis B vaccination | Conditional | Three doses at 0, 1 and 6 months if susceptible | Indicated when all three markers are negative: no current infection, no immunity, no past exposure. A repeat course is considered for non-responders after the first series. |
Reading the combinations
These are the patterns you are most likely to see on a report.
- All three negative: susceptible. You have never been infected and are not immune. Vaccination is indicated.
- Anti-HBs positive, anti-HBc negative, HBsAg negative, immune from vaccination. The ideal result after a course.
- Anti-HBs positive, anti-HBc positive, HBsAg negative, immune from past infection that you cleared. No action needed, but it means you were infected at some point.
- HBsAg positive, anti-HBc positive, anti-HBs negative, current infection. Needs specialist assessment to determine whether it is acute or chronic and whether treatment is indicated.
- Anti-HBc positive alone: an ambiguous pattern with several explanations, usually needing repeat or additional testing.
Checking that the vaccine worked
Hepatitis B is one of the few vaccines where confirming the response is routinely recommended for certain groups. Testing anti-HBs one to two months after the final dose gives a clear answer: 10 mIU/mL or above means you responded.
Around one in twenty healthy adults does not respond adequately to the first course, and non-response is more common with increasing age, obesity, smoking, diabetes, kidney disease and immunosuppression. A second course produces a response in most of those who failed the first.
Who should have their response confirmed
Post-vaccination testing is not needed for everyone, but it is worthwhile for these groups.
- Healthcare workers and anyone with occupational blood exposure.
- Patients on dialysis or with chronic kidney disease.
- People who are immunocompromised or on immunosuppressive treatment.
- Sexual partners and household contacts of someone with chronic hepatitis B.
- Infants born to hepatitis B positive mothers.
- Anyone with chronic liver disease, where response rates are lower.
A falling antibody level is usually not a problem
Anti-HBs levels decline over the years after vaccination, and people sometimes retest and worry that protection has gone. For an immunocompetent person who responded to the original course, immune memory generally persists even when measurable antibody falls below 10 mIU/mL, and routine boosters are not usually recommended.
The exceptions are people on dialysis and those who are significantly immunocompromised, where periodic monitoring and boosters are part of standard care.
Frequently asked questions
What do HBsAg, anti-HBs and anti-HBc mean?
HBsAg positive means current infection. Anti-HBs positive means immunity, from vaccination or from clearing past infection. Anti-HBc positive means exposure to the actual virus. It is never produced by the vaccine, so it is what distinguishes vaccinated people from those who were infected and recovered.
What anti-HBs level means I am protected?
10 mIU/mL or above is the standard threshold for protection, measured one to two months after completing the vaccination course.
Should I test after having the hepatitis B vaccine?
Not everyone needs to, but it is recommended for healthcare workers, dialysis patients, immunocompromised people, household and sexual contacts of infected individuals, and anyone with chronic liver disease, groups where non-response is more likely and matters more.
What if I did not respond to the vaccine?
Around one in twenty healthy adults does not respond to the first course. A second three-dose series produces a response in most of them. Persistent non-response after two courses is managed differently and warrants a specialist discussion.
My antibody level has dropped. Do I need a booster?
Usually not. If you responded to the original course and are immunocompetent, immune memory generally persists even when the measurable antibody level falls. Routine boosters are recommended mainly for dialysis patients and significantly immunocompromised people.
Book your hepatitis B serology test
We run the full panel rather than a single marker, so you get a clear answer about whether you are susceptible, immune, or need specialist follow-up.
Before you rely on this page
This page is general health information, not personal medical advice. Vaccine schedules depend on your age, medical history, pregnancy status, medications and previous immunisations. Our doctors will confirm what is right for you at your appointment. National recommendations are also revised periodically. We review these pages against current Indian and WHO guidance.
Last reviewed: 2026-09-01
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