Lab result explainedInflammationLast updated November 10, 2026

Hepatitis B surface antibody (anti-HBs): what reactive, non-reactive and your titer mean

Hepatitis B surface antibody (anti-HBs) · Hepatitis B panel (surface antigen, surface antibody, core antibody) · reported in mIU/mL (numerically identical to IU/L); qualitative reports state reactive or non-reactive

Hepatitis B surface antibody (anti-HBs, sometimes written HBsAb) is the antibody your immune system makes against the outer coat of the hepatitis B virus. Its presence means you are protected, either because you were vaccinated or because you had the infection in the past and cleared it. The test is reported two ways: qualitatively, as 'reactive' (antibody present) or 'non-reactive', and quantitatively as a titer in milli-international units per millilitre (mIU/mL), where 10 mIU/mL or higher is the internationally accepted level of protection.

It is the opposite of the surface antigen test. Hepatitis B surface antigen (HBsAg) is a piece of the virus itself, and a positive result means current infection. Surface antibody is your response to that coat, and a positive result means immunity. The third standard test, hepatitis B core antibody (anti-HBc), is only made after real infection, never after vaccination, so it is the test that tells you whether your immunity came from a needle or from the virus. Read together, the three results sort nearly everyone into one of five groups: immune by vaccination, immune by past infection, currently infected, never exposed, or an uncommon pattern that needs a closer look.

Most people searching this page have had the test as part of a job, school, dialysis or pregnancy check, or to see whether a vaccine course from years ago has worn off. A 'reactive' result, or any number of 10 mIU/mL and above, is good news. A result under 10, or 'non-reactive', does not necessarily mean the vaccine failed; antibody levels fall with time while immune memory persists, and a single booster dose followed by a repeat test usually sorts out who truly needs a new course.

anti-HBs at a glance

What it is: the antibody that neutralizes hepatitis B; it appears after vaccination or recovery from infection and is the marker of immunity.
Protective (immune): 10 mIU/mL or higher, reported as 'reactive' or 'positive'. Under 10 mIU/mL ('non-reactive') is non-immune or waned.
Levels above 100 are a strong response; many labs cap the report at '>1000 mIU/mL'. There is no such thing as too high.
Reactive anti-HBs with a negative core antibody = immune from vaccination. Reactive anti-HBs with a positive core antibody = immune from past infection. Surface antigen positive = current infection.
If you are under 10 after a full vaccine course, the usual step is one more dose and a repeat test 1 to 2 months later; about 5 to 10 percent of adults do not respond to two full courses.
No diet, herb or supplement changes this result. Vaccination, timing and the health conditions that blunt vaccine response are what move it.

Have your whole report? Paste it into the free Lab Explainer

Every marker explained in plain language, in context with the others, with questions to bring to your appointment. No account needed.

What anti-HBs measures

The hepatitis B virus is wrapped in a protein coat called the surface antigen. Vaccines contain only that coat, made by yeast, so they teach the immune system to recognize the virus without any risk of infection. Whether the coat comes from a vaccine or from a real infection, B cells respond by producing anti-HBs, which binds the coat and stops the virus entering liver cells. The lab measures this antibody with an immunoassay calibrated against a World Health Organization standard, which is why results are given in international units and comparable across countries.

Qualitative reports ('QL') state reactive or non-reactive using a cutoff that corresponds to 10 mIU/mL on most platforms. Quantitative reports give the number, typically from under 10 up to a ceiling such as 1,000 mIU/mL; a result of '>1000' simply means the antibody exceeded the assay's upper measuring range and the lab did not dilute further. Protection is a threshold, not a dose: 12 mIU/mL and 1,200 mIU/mL are both immune, although a higher value will take longer to fall below 10.

Timing matters. After the final vaccine dose, anti-HBs peaks at about one month, so post-vaccination testing is done one to two months later; earlier testing under-reads, and testing years later measures decline rather than response. After natural infection the antibody appears weeks to months after the surface antigen disappears, with a 'window period' when both are negative and only core antibody is present. Hepatitis B immune globulin (HBIG) and intravenous immunoglobulin lend passive anti-HBs for three to six months, and newborns carry maternal antibody for up to a year, both of which can produce a reactive result that is borrowed rather than earned.

Normal range for anti-HBs

Reference ranges vary between labs and by age, sex and pregnancy. Use the range printed on your own report.

Group	Typical range (mIU/mL (numerically identical to IU/L); qualitative reports state reactive or non-reactive)	Notes
Non-reactive / non-immune	Below 10 mIU/mL	Never vaccinated, incomplete course, waned antibody, vaccine non-responder, or tested too soon after the last dose. Some assays use a cutoff of 8 or 12; use the one on your report.
Reactive / immune, lower range	10–100 mIU/mL	Protective by CDC and WHO criteria. A value of 10 to 50 many years after vaccination is a typical waned level; immune memory is intact and no booster is needed for most people.
Reactive / immune, strong response	100–1,000 mIU/mL	Typical one to two months after a completed course in healthy adults. Some countries' occupational-health rules prefer 100 or more in healthcare workers; the US uses 10.
Reactive, above assay range	Reported as '>1000 mIU/mL'	A very strong response, common after a full course or recovery from infection. Nothing about it is harmful or abnormal.
Immune from vaccination (pattern)	anti-HBs reactive, anti-HBc negative, HBsAg negative	Vaccines never produce core antibody, so a negative core antibody with a reactive surface antibody means vaccine immunity.
Immune from past infection (pattern)	anti-HBs reactive, total anti-HBc positive, HBsAg negative	Resolved infection. The virus can persist in a dormant form in the liver and may reactivate under strong immunosuppression, so this pattern is flagged before chemotherapy, rituximab or transplant.
Chronic infection (pattern)	HBsAg positive for more than 6 months, anti-HBc positive, anti-HBs usually negative	A small minority of chronically infected people have both surface antigen and surface antibody at once; the antigen result takes precedence and infection is managed as active.
Isolated core antibody (pattern)	anti-HBc positive only; anti-HBs and HBsAg negative	Resolved infection with lost surface antibody, a false-positive core antibody, the window period of acute infection, or (rarely) low-level chronic infection. A single vaccine dose with a repeat anti-HBs often clarifies.
Susceptible (pattern)	All three negative	Never infected and not immune; vaccination is recommended for all adults aged 19 to 59 and for older adults with risk factors.

Reactive (positive) hepatitis B surface antibody

A reactive or positive hepatitis B surface antibody, or any titer of 10 mIU/mL or more, means you have protective antibody against hepatitis B. For the large majority of people in the United States this reflects the childhood or adult vaccine series, which has been routine for infants since 1991. If your core antibody is negative, that is the whole story: you are immune by vaccination and, if your immune system is normal, you do not need boosters, even if the level drifts below 10 years from now, because the memory cells that made the antibody persist and respond within days to any exposure.

If the core antibody is also positive, your immunity came from a hepatitis B infection that your body cleared, often without you ever knowing you had it; about 95 percent of adults who catch hepatitis B recover fully. You are not infectious and do not have liver disease from it, but the virus leaves a dormant template inside liver cells. That is harmless in ordinary life, yet it can reactivate under strong immunosuppression, so anyone with this pattern who is about to start chemotherapy, rituximab, high-dose steroids, biologic drugs or a transplant is monitored or given preventive antiviral treatment.

Height of the titer tells you how strong or recent the response is, not how 'well' you are protected. Values above 100 mIU/mL are typical soon after a completed course; '>1000' is common and simply exceeds the assay's range. The handful of situations where a reactive result does not mean your own immunity are passive antibody from HBIG or IVIG given in the past few months, maternal antibody in a baby under about 12 months, and the uncommon case of chronic infection in which surface antigen and antibody coexist, which is why the full panel is read rather than the antibody alone.

Common causes

Completed hepatitis B vaccination
Three doses of a standard vaccine (or two doses of the adjuvanted Heplisav-B) produce protective antibody in more than 90 percent of healthy adults under 40 and about 75 to 90 percent of those over 40. Core antibody stays negative.
Resolved past hepatitis B infection
Surface antibody appears weeks to months after the virus is cleared and the surface antigen disappears, alongside a positive core antibody. About 95 percent of adults and 5 to 10 percent of infected newborns clear the infection.
Hepatitis B immune globulin (HBIG) or intravenous immunoglobulin
Given after a needlestick, to newborns of infected mothers or after liver transplant, these contain ready-made anti-HBs that lasts three to six months and produces a reactive test that is not the person's own immunity.
Maternal antibody in infants
Babies carry their mother's antibody for up to 12 to 15 months, so infant testing is done at 9 to 12 months of age (and at least a month after the last vaccine dose) to measure the baby's own response.
Chronic hepatitis B with coexisting antibody
A small minority of people with chronic infection have low-level anti-HBs that does not neutralize their particular strain. The positive surface antigen is what counts, and they remain infectious.
Recent vaccine dose
Antibody rises within two to four weeks of a dose, so a reactive result shortly after a booster is expected; note that the vaccine's antigen can also make the surface antigen test transiently positive for up to two to three weeks after an injection, a well-known false positive.

Symptoms that can go with it

None; a reactive surface antibody causes no symptoms and signals protection
If the core antibody is also positive, there may be no history of illness at all, since most hepatitis B infections in adults are silent
Fatigue, nausea, jaundice or dark urine years earlier would fit a past, cleared infection
New fatigue, jaundice or abdominal swelling in someone with resolved infection who has started immunosuppressive treatment needs prompt review for reactivation

Non-reactive (low or negative) hepatitis B surface antibody

A non-reactive result, or a titer below 10 mIU/mL, means there is not enough antibody in your blood to count as protected on this test. There are four common reasons, and they call for different responses. You may never have been vaccinated or may have had an incomplete course (many adults born before 1991 were never offered it). Your antibody may have waned: titers fall steadily after vaccination, and in a 30-year follow-up of people vaccinated as children and young adults in Alaska only about half still had 10 mIU/mL or more, yet 88 percent of those who had dropped below responded briskly to a single booster, showing their memory was intact and almost no one had developed infection in the meantime. You may have been tested too early, before one month after the last dose. Or you may be a true non-responder.

True non-response means a level under 10 mIU/mL one to two months after a second complete vaccine series, and it affects roughly 5 to 10 percent of healthy adults with the older vaccines, fewer with Heplisav-B. Being over 40, obesity, smoking, male sex, diabetes, chronic kidney disease, celiac disease, HIV and immunosuppressive medicines all lower the odds of responding, as does a vaccine injected into fat rather than muscle. Non-responders are tested for surface antigen and core antibody to make sure the explanation is not an existing infection, and if those are negative they are counted as susceptible: they should avoid exposure and will need hepatitis B immune globulin promptly if they are exposed.

The CDC does not recommend routine boosters for immunocompetent people who responded to their original course, because protection against clinically significant disease persists even after antibody falls below 10. Exceptions are people on hemodialysis, who are tested every year and boosted when under 10, and other immunocompromised people, who are tested and boosted as needed. For healthcare workers, students, dialysis patients, people with HIV, sexual partners and household contacts of infected people, and infants born to infected mothers, post-vaccination testing is standard; for everyone else a non-reactive result years later is not a sign that anything went wrong.

Common causes

Never vaccinated or incomplete course
Universal infant vaccination began in the US in 1991 and universal adult (19 to 59) vaccination was only recommended in 2022, so many adults have had no doses, or one or two of the three.
Waned antibody after a good initial response
Titers decline over 10 to 30 years; a level that was 500 mIU/mL at age 2 may be under 10 at age 25. Memory persists, and a single dose typically restores a level above 10 within one to two weeks.
Tested too soon or too late
Antibody peaks about one month after the last dose; testing before that under-reads. Testing more than a year later measures decline, not response.
Vaccine non-response
About 5 to 10 percent of adults do not reach 10 mIU/mL after two complete courses of conventional vaccine, more often with age over 40, obesity, smoking, diabetes and kidney disease. Heplisav-B achieves protection in about 90 to 95 percent, including many prior non-responders.
Immunosuppression and chronic illness
Hemodialysis (about 50 to 70 percent respond to standard dosing, which is why a double-dose formulation is used), HIV with a low CD4 count, organ transplantation, rituximab, methotrexate, TNF-blockers and cirrhosis all reduce the response.
Injection into fat rather than muscle
The vaccine must reach the deltoid muscle; in heavier adults a standard 1-inch needle may not, and CDC advises a longer needle for people over about 200 lb (women) or 260 lb (men). Buttock injection is a known cause of poor response.
Current chronic hepatitis B infection
People with chronic infection do not make a protective surface antibody. A non-reactive anti-HBs with a positive surface antigen and core antibody is infection, not vaccine failure.

Symptoms that can go with it

None; being non-immune does not cause symptoms, it only means you are not protected
If the surface antigen is positive, there may be fatigue, loss of appetite, nausea, right upper abdominal discomfort, dark urine or jaundice, though most chronic infection is silent
Joint pains and a rash can accompany acute hepatitis B in the weeks before jaundice

Read it alongside

Hepatitis B surface antigen (HBsAg) — the marker of current infection; it must be negative for a reactive antibody to mean immunity.
Hepatitis B core antibody (total anti-HBc) — positive only after real infection, so it separates vaccine immunity from recovered infection.
Hepatitis B core IgM antibody — positive in acute or recently acquired infection and in the window period when both surface markers are negative.
Hepatitis B e antigen and HBV DNA — measure how actively the virus is replicating in someone who is infected; not needed if you are simply immune.
ALT and AST — liver enzymes; raised levels with a positive surface antigen indicate active liver inflammation.
Hepatitis C antibody and HIV test — often ordered together, since the three share routes of transmission and co-infection changes management.
Hepatitis A antibody — tested alongside when a combined hepatitis A and B vaccine is being considered.
Platelets and albumin — fall in advanced liver scarring; checked when chronic infection is found.

What usually happens next

If you are reactive with a negative core antibody, you are immune by vaccination; keep a copy of the result, since employers, schools and dialysis units ask for it, and no booster is routinely needed unless you are on dialysis or immunocompromised.
If you are reactive with a positive core antibody, you have recovered from past infection. Tell any clinician who proposes chemotherapy, rituximab, high-dose steroids, biologic therapy or a transplant, because reactivation can be prevented with antiviral medicine.
If you are non-reactive after a documented full course, the usual step is a single additional dose and a repeat test one to two months later; if still under 10, the series is completed (two more doses) and tested again.
If you are non-reactive with no vaccine record, start or complete the series; Heplisav-B is two doses a month apart, conventional vaccines are three doses over six months, and testing afterwards is only needed if you are in a group where it is recommended.
If you have had two full series and remain under 10, ask to be tested for surface antigen and core antibody, and discuss exposure precautions and the need for hepatitis B immune globulin after any exposure.
A reactive result in a baby under a year or within six months of HBIG or IVIG is repeated later to confirm it is the person's own antibody.

Diet, lifestyle and natural levers with evidence

What can move anti-HBs once the cause is known. Nothing here replaces finding the cause.

Complete the series and test at the right time

Strong evidence

Three doses of conventional vaccine (0, 1 and 6 months) or two doses of Heplisav-B (0 and 1 month) produce a protective antibody in 90 to 95 percent of healthy adults, and a trial of over 2,000 adults found Heplisav-B protected about 95 percent versus 81 percent for a three-dose comparator, with the gap widest in people over 60, with diabetes and with obesity. Post-vaccination testing one to two months after the last dose gives the true peak; testing at three weeks or at five years gives a lower number that does not reflect how well you responded. For someone whose level has merely waned, one booster dose produces a level above 10 mIU/mL within one to two weeks in the large majority.

Body weight, smoking and age shape the response; no supplement changes it

Moderate evidence

A meta-analysis of factors affecting vaccine response found that smokers were roughly 1.5 to 2 times as likely to fail to respond as non-smokers and that obesity roughly doubled the odds of non-response, partly because the injection lands in fat rather than muscle; age over 40 and male sex reduce the response as well. Stopping smoking and using a needle long enough to reach the deltoid both improve the odds. Trials of vitamin D, zinc and other supplements to improve hepatitis B vaccine response have been small and inconsistent, and none is recommended; no diet, herb or supplement raises or lowers your anti-HBs.

Time vaccination before immunosuppression, and use the right formulation if you have kidney disease or HIV

Strong evidence

Response rates fall sharply once rituximab, methotrexate, TNF-blockers, high-dose steroids or dialysis are under way, so the series is ideally completed before treatment starts or when kidney disease is still early. For dialysis patients, a double-strength formulation (40 µg per dose) or four doses raises protection from roughly 50 percent to 70 to 80 percent, and annual titers with a booster when under 10 mIU/mL are standard. People with HIV respond better when their CD4 count is above 350 and viral load is suppressed.

A reactive result obtained within six months of HBIG or IVIG, or in an infant under a year, may reflect borrowed antibody; repeat later before relying on it.

When to see a clinician promptly

A positive hepatitis B surface antigen result with jaundice, confusion, drowsiness, vomiting, easy bruising or severe abdominal pain: possible acute liver failure, which is an emergency.
A needlestick, sexual exposure or shared-needle exposure to someone with hepatitis B when your surface antibody is under 10 or unknown: hepatitis B immune globulin and vaccine work best within 24 hours and are recommended within 7 days.
Pregnancy with a positive surface antigen, or an unknown status, since treatment in the third trimester and prompt vaccination of the baby prevent most mother-to-child transmission.
A positive core antibody (with or without surface antibody) in anyone about to start chemotherapy, rituximab, high-dose steroids, a biologic or a transplant, because reactivation can be severe and is preventable.
Still under 10 mIU/mL after two complete vaccine courses, to be tested for infection and counselled as a non-responder.
Persistent fatigue, right upper abdominal pain, dark urine or pale stools with any positive hepatitis B marker.

Frequently asked questions

What does hepatitis B surface antibody QL reactive mean?

'QL' stands for qualitative, and 'reactive' means the antibody was detected above the protective cutoff, which corresponds to 10 mIU/mL on most assays. It means you are immune to hepatitis B. If your core antibody is negative the immunity came from vaccination; if it is positive you had and cleared the infection at some point. Either way you cannot catch hepatitis B in the ordinary course of life and are not infectious.

What is a normal anti-HBs level?

There is no 'normal' in the usual sense; the test is interpreted against a threshold. Under 10 mIU/mL is non-immune; 10 and above is immune. One to two months after a completed vaccine course, healthy adults usually have 100 to over 1,000 mIU/mL, and many years later 10 to 100 is typical. Any value at or above 10 is adequate, and a higher number does not mean better protection, only a longer time before it might fall below the cutoff.

What does a hepatitis B surface antibody >1000 mean?

Your antibody exceeded the top of the assay's measuring range, so the lab reported it as greater than 1,000 mIU/mL rather than diluting further. It is a strong response and is common after a full vaccine course, a recent booster or recovery from natural infection. It is not harmful, does not indicate infection and needs no action. If you also have a positive core antibody, it reflects a resolved past infection rather than vaccination.

Hepatitis B surface antibody non-reactive: do I need the vaccine again?

It depends on your history. If you never had the vaccine, or had only part of the series, you need a complete course. If you completed a course years ago, your antibody has probably waned while immune memory persists; the usual approach is one booster dose and a repeat test one to two months later, and most people come back above 10. If you remain under 10 after two complete courses you are a non-responder and should be checked for infection and counselled on precautions. Immunocompetent people who responded originally do not need routine boosters, with the exception of dialysis patients.

What is the difference between hepatitis B surface antibody and surface antigen?

The surface antigen (HBsAg) is part of the virus; a positive result means you currently have hepatitis B and can pass it on. The surface antibody (anti-HBs) is your immune system's response to that part; a positive result means you are protected. They are normally mutually exclusive: as an infection clears, the antigen disappears and the antibody appears. The third test, core antibody, is made only after real infection and tells you whether a positive antibody came from vaccination or from recovering from the virus.

How long after the hepatitis B vaccine should I get a titer?

One to two months after the final dose. Antibody rises over the first few weeks and peaks at about a month; testing earlier under-reads, and testing at three months or later starts to measure decline rather than peak response. For infants born to infected mothers, testing is done at 9 to 12 months of age, at least a month after the last dose. If a long time has passed since your series and the level is now under 10, that reflects waning, not failure.

Can a hepatitis B surface antibody test be falsely positive?

Rarely in the usual sense, but a reactive result can reflect antibody you did not make yourself: hepatitis B immune globulin or intravenous immunoglobulin given in the previous three to six months, or maternal antibody in a baby under a year. In those cases the test is repeated later. Separately, the surface antigen test (not the antibody test) can be transiently positive for two to three weeks after a vaccine dose because the vaccine contains the antigen, which occasionally alarms people tested right after an injection.

Who needs a hepatitis B titer checked?

Healthcare and public-safety workers, students in clinical programs, people on hemodialysis, people with HIV or other immunocompromise, sexual partners and household contacts of someone with hepatitis B, infants born to mothers with hepatitis B, and anyone with a documented exposure. For everyone else, routine titers after vaccination are not recommended, and a low level found by chance years later in a healthy adult who completed the course is not a reason for concern.

References

Hepatitis B. MedlinePlus, US National Library of Medicine (2024)
Schillie S, Vellozzi C, Reingold A, et al.. Prevention of hepatitis B virus infection in the United States: recommendations of the Advisory Committee on Immunization Practices. MMWR Recommendations and Reports (2018)
Weng MK, Doshani M, Khan MA, et al.. Universal hepatitis B vaccination in adults aged 19–59 years: updated recommendations of the Advisory Committee on Immunization Practices — United States, 2022. MMWR Morbidity and Mortality Weekly Report (2022)
Hepatitis B: clinical overview and serologic test interpretation for health professionals. Centers for Disease Control and Prevention (2024)
Terrault NA, Lok ASF, McMahon BJ, et al.. Update on prevention, diagnosis, and treatment of chronic hepatitis B: AASLD 2018 hepatitis B guidance. Hepatology (2018)
Bruce MG, Bruden D, Hurlburt D, et al.. Antibody levels and protection after hepatitis B vaccine: results of a 30-year follow-up study and response to a booster dose. Journal of Infectious Diseases (2016)
Jackson S, Lentino J, Kopp J, et al.. Immunogenicity of a two-dose investigational hepatitis B vaccine, HBsAg-1018, using a toll-like receptor 9 agonist adjuvant compared with a licensed hepatitis B vaccine in adults. Vaccine (2018)
Yang S, Tian G, Cui Y, et al.. Factors influencing immunologic response to hepatitis B vaccine in adults. Scientific Reports (2016)
Hepatitis B. World Health Organization fact sheet (2024)View source
Hepatitis B. Mayo Clinic (2024)View source
Hepatitis B, acute. Merck Manual Professional Version (2024)

Related markers

Related conditions

Evidence guides

Worried about your number?

Ask AskMN what your anti-HBs result could mean in the context of your other results, symptoms and medications. Free, unlimited, no account needed.

Ask about my anti-HBs

This page is educational and is not medical advice or a diagnosis. Lab results have to be interpreted together with your history, symptoms and other results by a clinician who knows you. Do not start or stop a supplement to change a lab value before the cause is known.