Hepatitis B Core Antibody, Total (Anti-HBc)

An antibody your body makes after hepatitis B infection. A positive result is linked to past or current infection. The vaccine does not cause it.

AI-verified against cited sources. Awaiting expert reviewAlso called Anti-HBc, HBcAb, Total anti-HBcLOINC 13952-7

What it is

Anti-HBc is an antibody to the core of the hepatitis B virus. The test counts both the early (IgM) and later (IgG) forms, so it's called total. It shows up early in an infection and usually stays positive for life, even after the virus is gone. The hepatitis B vaccine does not cause a positive result, because the vaccine contains only the surface protein.

Why it matters

This test shows whether you have ever been exposed to hepatitis B. It's one of the three tests in the standard hepatitis B panel, with HBsAg and anti-HBs. Read together, they show whether someone is infected, has recovered, is protected by vaccination or has never been exposed. It also matters before treatments that weaken the immune system, such as chemotherapy, because an old infection can sometimes become active again.

If it’s high

A positive result usually means your immune system has met the hepatitis B virus at some point. On its own, it can't say when, and it can't say whether the virus is still active. Your HBsAg and anti-HBs results fill in the picture. Most often it reflects an infection your body cleared long ago. Sometimes it's the only positive result (called an isolated core antibody), which has several possible explanations, including a false positive.

Common causes

A past hepatitis B infection that has cleared, often with a positive anti-HBs
A current new or long-term hepatitis B infection (HBsAg positive)
An isolated core antibody: antibody from a past infection whose anti-HBs level has faded below detection
A false-positive result, which repeat testing can help sort out
Antibody passed from a mother with hepatitis B to her baby before birth (temporary in the baby)

What can help

Ask your clinician how to read your three hepatitis B results together
Ask whether a repeat test or a hepatitis B viral load (HBV DNA) test is needed, especially if this is your only positive result
If you will start chemotherapy or another treatment that weakens the immune system, tell your care team about this result so they can plan

What can affect your result

Vaccination does not cause a positive result
Different assays can disagree on weak results, so an isolated positive is often repeated with the same assay
Biotin supplements can interfere with some immunoassays
A baby can carry its mother's antibody for a time after birth
Mayo Clinic Laboratories asks patients to avoid biotin (vitamin B7) supplements for 24 hours before its total anti-HBc test.
Weak or isolated positive results can differ between assay brands. The CDC suggests repeating an isolated positive with the same assay.
A baby can carry its mother's anti-HBc for a time after birth if she has hepatitis B, so the CDC does not advise anti-HBc testing before 24 months of age.

Appears with the onset of an acute infection and usually stays positive for life (CDC).

When to talk to a clinician

A positive result isn't an emergency by itself. Contact your clinician to go over it, especially if you are pregnant, have liver disease, are about to start chemotherapy or medicine that weakens the immune system, or have yellow skin or eyes, dark urine or severe tiredness.

Questions you could ask

Am I protected against hepatitis B, from vaccination or from a past infection?
What do my three hepatitis B results mean together?
Do I need a repeat test or a hepatitis B viral load (HBV DNA) test?
Does this result affect any treatment I am planning, such as chemotherapy or medicine that weakens the immune system?

Questions people ask

Does a positive anti-HBc mean I'm immune?

Not on its own. If you also have a positive anti-HBs and a negative HBsAg, that usually means you had hepatitis B in the past and recovered, and you're immune. If anti-HBs is negative, your clinician may want to repeat the test or add others.

Could my positive result be a false positive?

Yes, sometimes, especially when it's the only positive hepatitis B result. The CDC suggests repeating the test with the same assay. If it turns out to be a false positive, you are not immune, and hepatitis B vaccination may be offered.

Will the hepatitis B vaccine make this test positive?

No. The vaccine contains only the surface protein, so it causes anti-HBs but not anti-HBc. A positive anti-HBc is linked to exposure to the virus itself.

Show the science and sources

For clinicians and researchers

Total anti-HBc (IgG plus IgM) appears at the onset of symptoms in acute hepatitis B and persists for life, so it marks exposure at an undefined time (CDC). Vaccination uses recombinant HBsAg only and does not induce anti-HBc. In the CDC interpretation table, HBsAg-negative, anti-HBc-positive, anti-HBs-positive is resolved infection. HBsAg-negative, anti-HBc-positive, anti-HBs-negative (isolated core) can be resolved infection with waned anti-HBs, occult infection, passive transfer to an infant of an HBsAg-positive mother, a false positive, or an HBsAg mutant that the assay misses. CDC (2023) advises repeating an isolated result with the same assay and testing HBV DNA in immunosuppressed patients. AASLD 2018 adds that some people with isolated anti-HBc have chronic infection with prior HBsAg clearance and remain at risk for liver cancer. Reactivation risk during immunosuppression depends on the regimen, which is why anti-HBc is checked beforehand. Mayo Clinic Laboratories performs this as an electrochemiluminescence immunoassay and notes that interpretation depends on the clinical setting.

LOINC 13952-7 (primary), 16933-4, 83100-8. Specimen: serum-or-plasma.

Sources

Clinical Testing and Diagnosis for Hepatitis B, CDC
Screening and Testing for Hepatitis B Virus Infection: CDC Recommendations — United States, 2023, MMWR Recommendations and Reports (CDC) (2023)
Update on Prevention, Diagnosis, and Treatment of Chronic Hepatitis B: AASLD 2018 Hepatitis B Guidance, Hepatology (AASLD) (2018)
Hepatitis B Virus Core Total Antibodies Screen, Serum (test HBCSN), Mayo Clinic Laboratories (Extended Catalog)
Hepatitis B Virus Past Exposure Panel, Serum (test HBPES), Mayo Clinic Laboratories (Extended Catalog)
Understanding Your Hepatitis B Test Results, Hepatitis B Foundation

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.