Your healthcare provider can use a few different tests to see if you HAVE hepatitis, how MUCH of the virus is present in your body, and if any liver damage has already been done.
One test is called a "liver enzyme test." This blood test looks at a number of substances in your blood that have to do with the liver, and will help your healthcare provider find out if your liver is working normally, or if it's being injured. If the test shows that your liver enzymes are higher than normal, it means that the liver IS being damaged. But this test CAN'T show if hepatitis C is causing the liver damage. Sometimes, the liver enzyme test results are normal, but you still have an infection that's causing liver damage. The next step in either of these cases is to find out if the hepatitis virus is causing the damage.
This can be done with a second type of blood test called the "viral RNA test." This test shows whether or not the hepatitis C virus is in your body, and if it is, it will also tell how MUCH of the virus is there. This is done by detecting the amount of virus RNA, or genetic material, that's in your blood.
Your healthcare provider will also use a blood test to find out which genotype of the hepatitis virus you have. This will be very important in planning your treatment program.
To help see how much liver damage has been done, your healthcare provider can do a procedure called a "liver biopsy." Now on this procedure, a small sample of tissue is taken from your liver with a needle, and then looked at under a microscope for signs of hepatitis and liver damage.
By performing some or all of these tests, your healthcare provider can find out whether or not you have hepatitis C, how much of the virus is present, and the amount of liver damage that's been caused.