Hepatitis B Core Antibody (IgM) - Serum
This test measures the presence of IgM antibodies to the hepatitis B core antigen in your blood. IgM antibodies typically appear early in an infection and can help identify recent or acute hepatitis B virus (HBV) exposure.
["Detects recent hepatitis B infection with IgM antibodies to the core antigen."]
Key facts at a glance
- LOINC
- 109969-6
- Short code
- HBV core IgG Msmt Ser
- Synonyms
- HBV core IgG Msmt Ser
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Does This Test Measure?
The test looks for IgM antibodies against the hepatitis B core antigen, which are produced by your immune system shortly after infection. These antibodies are a sign that your body is actively fighting an HBV infection, often within weeks of exposure.
Why Is This Test Important?
This test helps doctors determine if you have recently been infected with hepatitis B. Unlike other hepatitis B markers, IgM antibodies appear earlier in the infection timeline and can help distinguish between acute and chronic HBV infection.
When Might You Need This Test?
You may need this test if you have symptoms like fatigue, jaundice (yellow skin/eyes), abdominal pain, or if you’ve been exposed to hepatitis B (e.g., through medical procedures, sexual contact, or sharing needles). Healthcare providers may also order it for routine screening in high-risk groups.
What Does a Positive Result Mean?
A positive result means your immune system is actively producing IgM antibodies to the hepatitis B core antigen, suggesting recent HBV infection. This does not mean you are currently contagious in all cases, but it indicates you need further evaluation by a healthcare provider.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
A positive IgM antibody result is critical because it often signals an acute infection. This test alone cannot confirm the stage of infection or long-term health effects, so follow-up tests (like hepatitis B surface antigen or antibody tests) may be needed. Chronic infection can develop if the virus persists beyond the acute phase, so early detection is key for management and treatment planning.
Short name
HBc IgM
Frequently asked questions
How is this test different from other hepatitis B tests?
What are the most common symptoms of hepatitis B that this test helps detect?
Can I get this test at home, or do I need to visit a lab?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy