Common Hepatitis B and C Blood Tests
Persons chronically infected with hepatitis B or C should receive regular (at least six-monthly) blood tests to monitor their hepatitis status and liver function. To understand the tests, you need to understand two basic terms:
- a foreign substance in the body, such as the hepatitis B or C viruses
- a protein that your immune system makes in response to a foreign substance. Antibodies can be produced in response to a vaccine or a natural infection.
The Hepatitis B Markers
Indicates the presence of the hepatitis B virus by detecting the surface antigen (i.e. indicates current infection). Positive in all persons chronically infected with the virus but can also indicate short term (acute) infection.
Detects whole live hepatitis B virus present in the blood and indicates active viral replication. Persons chronically infected with hepatitis B and also HBeAg-positive are more at risk of passing the virus to others. Many eventually lose e-positive status, though this marker can flip-flop between positive and negative before settling. 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.
Detects the antibody to the hepatitis B virus and usually indicates immunity, but occasionally positive in a chronically infected person. This antibody is also formed in people given hepatitis B vaccine.
Indicates past or current hepatitis B infection.
Detects hepatitis B viral particles present in the blood (very sensitive and expensive test).
The Hepatitis C Markers
Detects the antibody to the hepatitis C virus and indicates current or past infection.
HCV RNA (or PCR test)
Detects hepatitis C viral particles present in the blood (the only way to confirm current hepatitis C infection).
The Liver Function Tests (LFTs)
Liver enzymes are released into the bloodstream at increased rates due to liver damage which can have a variety of causes and can lead to cirrhosis. These causes can include chronic active hepatitis from hepatitis viruses, damage due to toxins including alcohol, or causes such as fatty liver (common in people who are overweight or with diabetes). The results of liver function tests indicate when further investigation is required.
ALT (Alanine Aminotransferase)
ALT is the liver enzyme monitored most closely in hepatitis B or C carriers. It can provide an indication of whether they would benefit from treatment.
AFP (Alpha Fetoprotein)
This test is used as a marker for liver tumours (cancer) in people with chronic hepatitis B or C. High AFP levels can indicate the possibility of liver cancer. AFP is also elevated in pregnant women, but this is quite normal.
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