Exams and Tests

Your doctor will diagnose hepatitis B based on a physical exam and blood tests. He or she also will ask about your medical history (including possible risks for the virus, such as your job and sexual activity).

Blood tests to diagnose hepatitis B

Blood tests are done to help diagnose hepatitis B. They include:

• Hepatitis B antigens and antibodies. These help tell if you are or were infected with the virus. They also can show if you have been immunized and if you have long-term (chronic) infection. You also may get tested for the virus's genetic material (HBV DNA). For more information, see Hepatitis B Virus Tests.
• Tests to see if the hepatitis A, hepatitis C, or Epstein-Barr viruses are causing your hepatitis.
• Tests to see if you are infected with hepatitis D along with hepatitis B.

Hepatitis B and C: Should I Be Tested?

Blood tests to check for liver damage

Blood tests may be done to help find out if your liver has been damaged. They include:

• Bilirubin, albumin, and prothrombin time. These help show how well your liver is working. Cholesterol testing also may be done.
• Alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, and lactic dehydrogenase (LDH). These show whether your liver is damaged or inflamed.

Tests if you are having treatment or are thinking about it

Tests may be done if you have chronic hepatitis and are considering antiviral treatment. These tests also may be used to find out whether treatment has helped control liver damage. The tests include:

• Imaging tests.
  • Abdominal ultrasound
  • CT scan
  • MRI (may be used in rare cases)
• Removing a tissue sample from the liver (liver biopsy).

Test for liver cancer

An alpha-fetoprotein (AFP) test may be done. If the AFP level is high, it may point to liver cancer.

Follow-up visits

If you have chronic infection, you will need to visit your doctor regularly. He or she will do blood tests to check your liver function and the activity of the virus in your body.

Some of the tests can tell your doctor if the virus is multiplying in your liver. This raises your risk for chronic hepatitis.

Early detection

The Centers for Disease Control (CDC) recommends that all pregnant women have the hepatitis B surface antigen test. The test can show if a woman has a current hepatitis B infection. This test also may be repeated later in the pregnancy if a woman is at high risk for infection. For more information, see What Increases Your Risk.

You can be tested for hepatitis B before getting vaccinated.

• Antibody testing will show if you have an active hepatitis B infection and need treatment.
• If testing shows that you are already protected against hepatitis B, you won't need to get the hepatitis B vaccine(What is a PDF document?).
• It's not harmful to get the vaccine even if you already have antibodies against the virus in your blood.