Chronic hepatitis C infection often has no symptoms. It is usually first suspected when a blood test shows an elevation in liver enzymes.
One liver enzyme called alanine aminotransferase (ALT) can indicate hepatitis C infection when elevated. Many infections, toxins, and diseases can cause elevations in ALT. Your doctor must perform specific hepatitis C tests to confirm the diagnosis.
Chronic hepatitis C is a persistent infection by the hepatitis C virus (HCV). Acute hepatitis C refers to the initial illness from infection within six months of becoming infected. Most people (up to 80%) with acute hepatitis C move on to chronic hepatitis C infection. The general term hepatitis refers to an inflammation of the liver, which can also be caused by non-viral causes.
The first test for hepatitis C infection is a blood test for hepatitis C antibody. Your body produces this antibody when it is infected with the hepatitis C virus. The name of this blood test is the enzyme-linked immunosorbant assay (ELISA).
The ELISA test is not perfect. It may indicate a hepatitis C infection when you do not actually have one. If the ELISA is positive, your doctor may do a recombinant immunoblot assay (RIBA) test to help confirm a hepatitis C infection.
When the RIBA test indicates a hepatitis C infection, the results are compared to the ALT levels. If the ALT levels are elevated, and the ELISA and RIBA tests are positive, it’s likely you have a chronic hepatitis C infection. Another test called a polymerase chain reaction (PCR) may be done to determine current activity of the virus.
Before treatment starts, the patient may have a liver biopsy. A biopsy determines the amount of liver damage caused by the virus. In this procedure, the doctor inserts a special biopsy needle through the skin and into the liver. A small sample of liver tissue is removed. Another test used for determining damage to the liver is called a Fibrosure blood test.
Hepatitis C tests may be positive in someone who was previously infected with the hepatitis C virus but whose immune system was able to clear the infection. Liver enzyme levels are usually normal in these people. The PCR test provides more information.
The PCR detects the genetic material of the hepatitis C virus living in your body. If you have a positive ELISA, RIBA, and PCR, and normal liver enzymes, you may be a hepatitis C carrier. This means the hepatitis C virus is in your body, but you do not have any major liver damage. In general, these people do not need immediate treatment. The doctor will monitor the liver enzymes. If an elevation in ALT were to occur, treatment would then be considered.
Someone with positive ELISA and RIBA, negative PCR, and normal ALT would be considered to have recovered from a hepatitis C infection. However, a single negative PCR could mean that amount of virus in the body has temporarily fallen below the detection limits of the test. Your doctor may repeat the PCR test to confirm that the infection is gone.