Additional Blood Tests
HBeAg (Hepatitis B e-Antigen) - This is a viral protein that is secreted by hepatitis B infected cells. It is associated with chronic hepatitis B infections and is used as a marker of active viral disease and a patient's degree of infectiousness.
- A positive result indicates the person has high levels of virus and greater infectiousness.
- A negative result indicates low to zero levels of virus in the blood and a person is considered less infectious.
This test is often used to monitor the effectiveness of some hepatitis B therapies, whose goal is to convert a chronically infected individual to "e-antigen negative".
The absence of e-antigen, however, does not necessarily exclude active viral replication. Some patient groups have mutant viruses that do not give rise to e-antigen. Patients with negative e-antigen, but detectable viral DNA, are traditionally thought to be more resistant to conventional treatment than those who have positive e-antigen levels.
HBeAb or anti-HBe (Hepatitis B e-Antibody) - This antibody is made in response to the e-antigen and is detected in patients who have recovered from hepatitis B infections as well as those who are chronically infected. Chronically infected individuals who stop producing e-antigen sometimes produce e-antibodies. The clinical significance of this result is unclear but it is generally considered to be a good thing. In rare cases, anti-HBe may be associated with active viral replication in patients with e-antigen negative virus mutations.
Liver Function Tests (or Liver Enzymes) - Includes blood tests that assess the general health of the liver. When elevated above normal values, the ALT (alanine aminotransferase) and AST (aspartate aminotransferase) tests indicate liver damage. They are enzymes located in liver cells that can leak out into the bloodstream when liver cells are injured.
- ALT (alanine aminotransferase) is the liver enzyme marker that is followed most closely in those chronically infected with hepatitis B. This test is useful in deciding whether a patient would benefit from treatment, or for evaluating how well s/he is responding to therapy.
AFP (Alpha-FetoProtein) - This is a normal protein produced in the developing fetus. Pregnant women will have elevated AFP's. Other adults, however, should not have elevated AFP in their blood. This test is used as a liver tumor marker for patients with chronic hepatitis B. Patients should have their AFP levels monitored routinely since high levels could indicate the possibility of liver cancer.
Ferritin - Iron is stored in the liver in the form of ferritin. Increased levels of ferritin means a high level of iron is being stored. This could result from an increased iron intake in the diet (vitamin supplements, food cooked in iron pots, etc.), but it can also occur from a destruction of liver cells causing leakage of ferritin. More research is needed to understand the relationship between elevated ferritin and liver cancer.A Guide to Common Blood Tests
Issue No. 2, October 2003