Hepatitis C is a viral infection which causes the liver to become inflamed and, over time, to scar or even cease functioning properly. It is caused by the hepatitis C virus, and is usually contracted through contact with the blood of an infected person. There are several different hepatitis C tests. Some are used to determine whether an individual has the virus. Once a preliminary diagnosis of hepatitis C has been made, a physician may run tests to determine the severity of the infection and the exact infection type, and to find out whether the liver has been damaged.
Before any other hepatitis C tests are performed, a physician usually performs a basic blood test to determine whether an individual is infected with the virus. During this test, a blood sample is studied for evidence of antibodies which have developed in response to the hepatitis C virus. If these antibodies are present, the tested individual has been exposed to the virus at some stage in his life. As hepatitis C often presents no symptoms until it reaches an advanced stage, this basic test is often performed only after an infected individual has sustained extensive liver damage.
Some hepatitis C tests are used to determine the severity of an infection. During these tests, a physician measures how much of the genetic material which makes up the hepatitis C virus is present in a blood sample. Large quantities of this genetic material usually indicate an active infection, and may prompt the physician to begin aggressive treatment tactics.
There are six distinct subtypes of the hepatitis C virus. Certain hepatitis C tests can help physicians determine exactly which viral subtype an individual has been infected with. Generally, this process involves taking a blood sample and then studying the genetic makeup of the hepatitis C virus found within it. Understanding viral subtype can help a physician choose the most suitable course of treatment.
Finally, some hepatitis C tests are performed to find out whether the infected person’s liver has been damaged by the virus. Some of these tests involve studying a blood sample to determine whether it contains materials which are normally eliminated from the bloodstream by the liver. Other tests may involve biopsying the liver, or using a needle to withdraw a tissue sample from the organ. This tissue sample is then studied for evidence of scarring and the buildup of fatty substances.