Diagnosis
When a patient has these symptoms, a hepatitis diagnosis can be confirmed with blood tests. However, chronic viral hepatitis can go undetected for years, unless the proper laboratory blood tests have been performed, and many patients have few to no symptoms until the disease has already caused liver damage. The doctor may recommend different types of blood tests to diagnose viral hepatitis:
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Liver enzyme tests
The doctor may recommend testing the levels of liver enzymes in the blood. When the liver cells are damaged, the enzymes can be detected in the blood. If the doctor detects very high levels of liver enzymes, it could signal viral hepatitis. However, high levels could also be caused by other substances that are damaging to the liver, such as alcohol, drugs, medications, and toxins. If the patient begins to show issues with hepatic synthetic dysfunction (i.e, elevated bilirubin levels leading to jaundice), then this may indicate a more severe liver injury.
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Viral antigen tests
An antigen is a harmful substance that causes the body to produce antibodies to fight it. When the body is exposed to an antigen, it produces antibodies to destroy it. For example, the doctor may recommend testing the blood for hepatitis antigens to determine if the virus is present in the body. These tests help to indicate if the virus is present, and allow the doctor to monitor the patient's response to treatment. These tests may include the Hepatitis B Surface Antigen (HBsAg) test and the Hepatitis B "e" Antigen (HBeAg) test.
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Viral antibody tests
Antibodies are substances produced by the body in order to fight off viruses and bacteria. The doctor can measure the presence of hepatitis antibodies in the blood in order to determine if the disease was present. In acute hepatitis, these antibodies can help to eradicate the virus and then remain in the blood to protect the patient from future infections as is the case with hepatitis B. Unfortunately with a positive hepatitis C antibody, this does not mean you have immunity to future exposures and possible subsequent reinfections. A hepatitis C positive antibody just indicates a possible exposure, while a positive viral load indicates an active infection, which is discussed in the next section.
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DNA/RNA tests
In order to infect the cells of the liver, the hepatitis virus attaches itself to the outside of the liver cells, allowing its genetic material (DNA for hepatitis B; RNA for hepatitis C) to invade the cell. This genetic material then takes over the cell's normal functions and uses the cell to reproduce and create many copies of the virus. The doctor may recommend testing the presence of hepatitis B DNA or hepatitis C RNA in the blood in order to determine the amount of active virus in the blood. These tests are very important in monitoring the patient's response to treatment. This test can also help determine how infectious the patient is, and their risk of spreading the disease to others. The doctor may also run genetic tests to determine the specific genotype of the disease. There are 8 genotypes of Hepatitis B and 6 genotypes of Hepatitis C. This information can help guide treatment decisions.
Ask your doctor for a blood test for Hepatitis C if:
- You received a blood product for clotting disorders before 1987
- You were ever an injection drug user
- You received an organ transplant or blood transfusion before July 1992
- You received blood from someone who later tested positive for hepatitis C
- You were born between 1945-1965 per CDC guidelines
- You had a recent blood exposure from a known hepatitis C patient
