What tests will your doctor run?

This test measures the amount (or level) of an enzyme called ALT that is made in liver cells. If liver cells are damaged or die, ALT leaks into the bloodstream. One goal of treatment is to bring high levels of ALT back to normal.

If the treatment is working, ALT levels often come down to normal. If the ALT level decreases quickly in the treatment process, this is a positive factor in the response to treatment.

This test measures the amount of hepatitis C virus in your blood. Treatment for hepatitis C is aimed at reducing the viral load, and specifically at making it negative (undetectable). "Undetectable" means that no virus is currently present in your blood. Your doctor will check your viral load at different times during treatment. Studies have shown that if the amount of hepatitis C virus in your blood after 12 weeks of being on medications falls by 100-fold (eg, 1 million international units of virus goes down to 10,000 international units), the chance that the hepatitis C virus will be gone once you have finished your therapy goes up.

In addition to the ALT level and viral load tests, your doctor will look at your complete blood count (CBC). This includes your white blood cells, which may be affected by interferon treatment. If the level of your white blood cells drops below a certain point, your doctor may change your interferon dose. A CBC also measures your red blood cells, which may be affected by ribavirin. If your red blood cell and hemoglobin levels drop below a certain point, your doctor may change your ribavirin dose.

For more information, see Understanding Lab Tests.