A patient seated in the chair before a blood draw
In person

Hepatitis B Core Antibody (IgM)

IgM core antibodies, linked to a recent hepatitis B infection.

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  • 2,000+ lab locations. Find one near you
  • Nothing due at the lab. FSA / HSA accepted
  • Ordered by a licensed clinician

At a glance

Collection
Blood draw
A standard blood draw at the lab.
Preparation
None
Nothing to do ahead of time. Water is fine.
Results
2 to 4 days
Typical turnaround after your visit.
Where
2,000+ lab locations
Nationwide, with nothing due at the lab.

About this test

This test measures IgM antibodies to the hepatitis B core protein. The lab describes this antibody as a marker of a recent (acute) hepatitis B infection. It is used for questions about a recent infection rather than routine screening, and it does not reflect immunity from vaccination.

For adults 18 and older. Test availability varies by lab location.

Who should take this test?

For adults with questions about a possible recent hepatitis B infection, often when a provider suggests it. If you have yellow skin or eyes, or a recent exposure, see a provider promptly.

Ask about this test

Not sure this is the right test?

AI-generated. For information only, not medical advice. Call 911 for an emergency.

What does this test measure?

Your result shows whether IgM core antibodies were found, which can help a healthcare provider tell whether a hepatitis B infection may be recent, read with other hepatitis B tests.

Hepatitis B core antibody, IgM
IgM core antibody is an early antibody to the core of the hepatitis B virus. It is found in most recent infections and can sometimes be the only sign of one. It is read with other hepatitis B results, such as surface antigen, to help show whether an infection may be recent.
Why it’s measured: Relates to a recent hepatitis B infection, read with your other hepatitis B results.

How it works

  1. Step 1

    Order online

    Check out here. A licensed clinician in your state reviews your order and sends it to the lab.

  2. Step 2

    Visit a lab

    Bring a photo ID to any of 2,000+ lab locations. No fasting needed, and nothing is due at the lab.

  3. Step 3

    Get your results

    Results post to your account, usually in 2 to 4 days, each number next to the lab’s reference range.

Find a lab near you

Choose from 2,000+ lab locations nationwide. Your order works at any of them.

What your results tell you

The result is reported as reactive or nonreactive for hepatitis B core IgM antibodies. The lab’s reference result is nonreactive.

  • Your number next to the lab’s reference range
  • Explained in plain language
  • A licensed clinician reviews your order and, if appropriate, orders the test.
  • A lab report you can download and share

A reactive result is read with other hepatitis B tests. A healthcare provider can explain what it means for you and the next steps.

Which hepatitis B test?

Similar names, different questions. Each marker tells a provider something else.

Core IgM

The early type of antibody to the core of the virus.

Looks for
IgM antibodies to the core protein
A positive relates to
A recent infection
Vaccination
Absent after vaccination alone

Clinical-grade testing, from the comfort of home.

From the lab to your report, every step of our process meets the gold standard in medical testing.

  • CLIA-certified labs

    Every lab we partner with is certified under the Clinical Laboratory Improvement Amendments, meeting both state and federal standards with regular independent inspections.

  • We protect your health data

    We protect your health data with encryption and do not sell it. Some results must be reported to public health authorities by law. See our Privacy Notice.

  • Rigorous quality assurance

    All partner labs run regular internal quality checks, participate in proficiency testing, and comply with federal and state lab regulations.

  • Clinician-reviewed reports

    Results are reviewed by an independent, licensed clinician.

Questions

Common questions.

Anything else, our care team answers by phone, text, or email.

The total core antibody test looks for both IgG and IgM antibodies to the hepatitis B core, which can reflect a past or current infection. This test looks for IgM alone. The lab describes core IgM as a marker of a recent infection, and in some cases it may be the main sign of one.

This test does not show whether you are immune to hepatitis B. The lab notes that core antibodies are absent in people who have been vaccinated, so a nonreactive result says nothing about vaccine immunity. It also does not measure the virus itself, so a provider reads it with other hepatitis B tests.

A reactive result means IgM core antibodies were found, which the lab links to a recent hepatitis B infection. A healthcare provider can explain what it means for you, whether other tests are needed, and the next steps for care.

Biotin supplements can affect some lab results, including this one, and can push them falsely high or falsely low. Tell your healthcare provider if you take biotin. Don’t stop or change any medicine or supplement without talking with your healthcare provider.

Some positive results are reported to public health authorities as required by state law. Talk with a healthcare provider about any positive result.