Virus Detection Tests
One thing doctors look for when comparing virus detection tests is sensitivity (how capable the test is of finding the hepatitis C virus in your body). A highly sensitive test provides a more accurate result because it's capable of detecting low levels of hepatitis C virus that a less-sensitive test might miss.
One virus detection test is called a PCR (polymerase chain reaction) test. In the case of the hepatitis C virus, the PCR measures the amount of virus in your body (viral load) by taking a sample of the blood and amplifying genetic material associated with the virus millions of times.
Liver Function Tests
Liver function tests (LFTs) are the most commonly used way to check for liver problems. These blood tests look for enzymes and other chemicals that are produced when the liver does its various jobs.
ALT (alanine aminotransferase) — ALT is an enzyme that is normally found in the liver cells and in the blood. When liver cells become damaged, they leak into the bloodstream, causing levels of liver enzymes to be raised. An increase in ALT levels can indicate acute liver damage. However, a single ALT test will not reveal the severity of liver damage. Many people with chronic hepatitis C have normal ALT levels, so this test is not considered a completely accurate marker of disease progression. Other liver enzymes that may be measured by blood tests include AST (aspartate aminotrasferase), GGT (gamma-glutamyl transferase), and alkaline phosphatase.
Bilirubin — When red blood cells complete their life cycle and break down naturally, they produce bilirubin, a yellow pigment that's passed on to the liver and excreted in the bile. Most of the time, the body produces as many red blood cells as it breaks down. However, if the red blood cells break down more rapidly or if liver function becomes impaired, bilirubin levels in the blood rise. In patients with hepatitis, bilirubin levels tend to fluctuate. A prolonged persistent rise in bilirubin for a patient with chronic hepatitis C usually indicates severe liver dysfunction.
Albumin — Albumin is a protein manufactured by the liver. A decrease in albumin may reflect a reduction in the liver's ability to synthesize this protein, and a significant sustained decrease in this protein may mean poor liver function. However, decreases in albumin levels may also occur for reasons not related to the liver. Your doctor will take this into account when interpreting test results.
Prothrombin time — This test measures blood clotting ability. When the liver is damaged, it may fail to produce blood clotting factors.
Liver Biopsy
In order to assess the progression of the disease, your doctor may perform a liver biopsy every 3 to 5 years.
This is a procedure in which a tiny sample of tissue from the liver is removed and examined in a laboratory. A liver biopsy is an essential tool in monitoring hepatitis C — in fact it is one of the best ways to measure the extent of liver damage. Liver biopsies are also important in ruling out any other forms of liver disease.
Today, liver biopsies are performed as outpatient procedures. General anesthesia is not necessary. Patients receive local anesthesia at the area where the needle will be inserted (usually the right side of the rib cage). Although the test itself only takes a few minutes — with the actual biopsy being done in seconds — you may be monitored at the testing facility for several hours.
Patients often describe the sensation they experience during the test as a feeling of strong pressure on the spot where the tissue is removed. About 10% of patients experience mild to moderate pain at the biopsy site. You may feel tired after the test, so it is a good idea to schedule some rest time after having a biopsy. You should speak to your doctor about the specific details and risks of liver biopsy.
The degree of liver damage measured from a liver biopsy is scored in stages:
- Stage I — In the earliest stage of liver damage, the liver is inflamed (immune cells called lymphocytes are present), but only minimal scarring has occurred. There is little damage to the liver at this point
- Stage II — In this early stage of liver damage, the liver is inflamed and mild scarring (fibrosis) has begun to form
- Stage III — In this stage, scar tissue from one area of the liver bridges (connects) to scar tissue from other areas, leading to more advanced fibrosis (scarring)
- Stage IV — In this advanced stage of liver damage, cirrhosis (advanced scarring) has occurred. At this point, the degree of damage to the liver may be serious and the liver's function may be so impaired that other body functions are severely weakened, too