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 for the core of HBV during the active stage of infection. 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 1 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. It can take 60 to 150 days to develop symptoms of hepatitis B after you become infected. 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, 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:
- Nausea
- Loss of appetite
- Muscle aches
- Fever
- Jaundice, or yellowed skin and eyes
- Dark-colored urine
- Belly pain
- Swelling and confusion. This is in extreme cases.
You may also have this test if you have a history that puts you at risk of 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 (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.
