Hepatitis B Virus Tests
Hepatitis B tests are blood tests that show whether you have an active hepatitis B infection. The tests can also show if you had the infection in the past.
The tests look for different signs of infection:
- Antigens, which are made by bacteria or viruses.
- Antibodies, which are made by the body to fight infection.
- Hepatitis B DNA, which is the virus's genetic material.
Hepatitis antibodies can take weeks or months to develop. So an infected person may test negative early in the infection.
Why It Is Done
You may need testing if:
- You have symptoms of hepatitis.
- You may have been exposed to the hepatitis B virus. You are more likely to have been exposed to the virus if you inject drugs, have many sex partners, or are likely to be exposed to body fluids (such as if you are a health care worker).
- You've had other tests that show you have liver problems.
- You are pregnant.
- You or your doctor wants to know if you are protected from getting the disease.
The tests also are done to help your doctor decide about your treatment and see how well it's working.
How To Prepare
In general, there's nothing you have to do before this test, unless your doctor tells you to.
How It Is Done
A health professional uses a needle to take a blood sample, usually from the arm.
How It Feels
When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.
There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.
Hepatitis B antibodies and/or antigens are found. More tests may be needed to see if you have an acute or chronic infection.
The test may also find hepatitis D antibodies, which means you have hepatitis D. This infection occurs only in people who are already infected with hepatitis B.