Hepatitis B Blood Tests
The hepatitis B virus specifically attacks the liver, so health care providers will order blood tests to monitor the health of your liver, typically every 6-12 months. Some of the most common liver related blood tests are described below.
These blood tests measure potential liver damage (or liver inflammation). If a person is infected with the hepatitis B virus, the liver cells can be injured by the virus. As a result, the liver enzymes can leak into the bloodstream. The higher the levels of these enzymes and other biomarkers, the greater the risk of potential liver damage. It is important to note that some of these blood tests can indicate liver damage or inflammation for reasons other than hepatitis B. That is why it is important to have a comprehensive evaluation by a knowledgeable health care provider who will take the time to discuss your results.
ALT or SGPT (alanine aminotransferase) is found almost exclusively in the liver and is monitored most closely in a chronic hepatitis B infection. This test is useful in deciding whether a patient would benefit from treatment or for evaluating how well a person is responding to therapy. The normal range for ALT in healthy adults is 29-33 U/L for men and 19-25 U/L for women. For purposes of guiding management of CHB, an upper limit of normal for ALT of 35 U/L for males and 25 U/L for females is recommended[1].
AST or SGOT (aspartate aminotransferase) is found in the liver, heart and muscle so is less accurate than the ALT in measuring liver damage. But this enzyme is often ordered to help monitor potential liver damage from the hepatitis B virus. The normal range is 30-35 IU/L for men and 20-25 IU/L for women3.
AFP (Alpha-FetoProtein) - This is a normal protein produced in the developing fetus; thus, pregnant women will have elevated AFP. Other adults, however, should not have elevated AFP in their blood. This test is used to screen for primary liver cancer patients with chronic hepatitis B. It is important to have AFP levels monitored since hepatitis B is the leading cause of liver cancer. If the AFP level is high, the health care provider will order more blood tests and imaging studies.
Bilirubin test measures the amount of bilirubin in your blood to help determine how well your liver is functioning. Bilirubin is a yellowish substance produced by the body when it breaks down old red blood cells. It passes through the blood stream to your liver which processes it and adds it to a fluid called bile. Bile exits your body through your intestine. A healthy liver removes most bilirubin from the body, but if the liver is damaged, bilirubin can leak into the blood. High levels of bilirubin in the blood can cause jaundice, a condition that turns the skin and eyes yellow.
A platelet count is a test that measures the number of platelets in your blood and is usually part of a complete blood picture (CBC). Platelets are cells that help your blood clot to avoid bleeding. Too many or too few platelets could be a sign of disease or an ill-functioning liver. Your liver plays an important role in maintaining a healthy number of platelets in your blood.