Hepatitis B Core Antibody
Does this test have other names?
IgM anti-HBc, HBcAb
What is this test?
This test looks for antibodies called IgM in your blood. The test is used to find out whether you are actively infected with the hepatitis B virus (HBV).
HBV has a central core and a surrounding envelope. Your immune system makes IgM antibodies to the core of HBV during the active stage of infection. It can take 60 to 150 days to develop symptoms of hepatitis B after you become infected. Hepatitis B core IgM antibodies begin to appear in your blood several weeks after you are first infected with HBV. People who have had the hepatitis B vaccine will not have the core antibody in their blood.
HBV is one of 5 hepatitis viruses. The others are hepatitis A, C, D, and E. Most hepatitis infections are caused by these 5 viruses. HBV is spread through blood, seminal fluid, and vaginal secretions. The virus causes an infection in the liver. In most cases, this virus clears up on its own within 6 months. But in a small portion of adults and a larger portion of children, the virus does not go away. This is especially true for newborns. This is called having a chronic infection. It may lead to liver cell damage; scarring, or cirrhosis; or liver cancer.
Why do I need this test?
You may need this test if your healthcare provider suspects you have a liver infection caused by HBV. You may also need this test if you have symptoms of hepatitis B. Symptoms usually start slowly. Many people have no symptoms or only feel like they have a mild case of the flu. You may not have symptoms until the infection is chronic or severe.
The most common symptom is extreme tiredness. Other symptoms may include:
You may also have this test if you have a history that puts you at risk for being in contact with the virus. Risk factors for hepatitis B infection include:
Having sex with someone infected with the virus
Living in close contact with someone who has the virus
Being a man who has sex with men
Being a child born to a mother who has the virus
Sharing needles for intravenous, or IV, drug use
Working in a healthcare center where you are exposed to blood
Getting a blood transfusion or organ transplant. This is less common with active screening.
What other tests might I have along with this test?
Your healthcare provider may order other blood tests to look for HBV. These tests can look for antigens on the surface, envelope, and core of the virus, as well as the antibodies to these antigens. Because the symptoms of all 5 hepatitis infections are much the same, this blood test is often done along with other hepatitis blood tests to tell your provider which type of virus you may have.
What do my test results mean?
Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.
Normal results are negative or nonreactive, meaning that no hepatitis B core IgM antibodies were found.
If your test is positive or reactive, it may mean you are actively infected with HBV. In most cases this means that you will recover within 6 months. If you recover, you will have immunity from the virus and will not be able to pass the virus to others. If you don't recover in 6 months, the virus may stay in your blood, cause liver problems, and can infect others. Your healthcare provider may give you medicines if you don't recover after 6 months.
How is this test done?
The test requires a blood sample, which is drawn through a needle from a vein in your arm.
Does this test pose any risks?
Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.
What might affect my test results?
Other factors aren't likely to affect your results.
How do I get ready for this test?
You don't need to prepare for this test.