Screening for hepatitis C is not routinely done so you may have to request a test from your medical provider. This usually involves an antibody test followed by a confirmatory HCV viral load test. Once hepatitis C is diagnosed, ongoing monitoring is needed to assess disease progression and the need for treatment. It is recommended that you use the same laboratory for all of your tests since result ranges and accuracy can vary from lab to lab. Keep copies of your lab and biopsy results for future reference.
HCV Antibody Tests:
Antibody tests measure proteins produced by the immune system to fight specific invaders. After exposure to HCV, it may take up to 26 weeks (the “window period”) before antibodies can be detected using a standard test. HCV antibodies are lifelong even after someone has been cured of HCV.
Viral Load Tests:
Viral load tests measure the amount of HCV RNA circulating in the blood. The presence of detectable genetic viral material indicates that the virus is actively replicating.
HCV viral load is expressed as International Units (IU/mL). There are three different types of viral load tests:
- HCV RNA polymerase chain reaction (PCR),
- branched-chained DNA (bDNA), and
- transcription-mediated amplification (TMA).
The PCR and TMA tests can detect viral loads as low as 5 IU/mL. The bDNA assay has a lower limit of detection of 615 IU/mL.
Viral load tests are used to confirm active HCV infection, to measure how well medications are working against the virus, and to establish whether someone has been cured of hepatitis C.
The association between viral load and disease progression has not been established—in other words, a high or low viral load does not translate into better or worse liver damage.
HCV Genotype Tests:
Genotype tests are used to determine what type(s)—also called “strains”—of HCV an individual carries. This information may be used to decide on the medications used to treat hepatitis C. There are 8 genotypes numbered 1 through 8. HCV Genotype 1 is the most common genotype (70-75%) in the United States followed by genotypes 2 and 3 (25-30%). The other genotypes are not as prevalent in the United States.
Biochemical or Liver Function Tests:
Various blood tests are used to assess how well the liver is working. Many of these tests measure non-specific markers of liver function. Liver enzyme tests are part of a hepatic panel (a group of clinical laboratory blood tests used to evaluate a patient with symptoms of liver disease or injury). The most common measurements of liver inflammation are alanine aminotransferase (ALT, formerly known as SGPT) and aspartate aminotransferase (AST, formerly known as SGOT). ALT and AST are enzymes released into the blood when liver cells are damaged. They are often—but not always—elevated in people with hepatitis C.
Many individuals with HCV have mild to moderate ALT and AST elevation, which is often the first indication that they are infected. In the past, ALT levels were assumed to be a marker of disease progression due to hepatitis C, but it is now known that some people with chronic hepatitis C experience serious liver disease progression with relatively normal ALT levels. This is why it is important for people with HCV to be monitored with a variety of tests, which may include a liver biopsy or a Fibroscan.
Other measurements of liver inflammation include alkaline phosphatase (ALK) and gamma-glutamyl transpeptidase (GGT). Abnormal levels may indicate cirrhosis or bile duct blockage, as well as other conditions. In addition, your doctor may measure INR (international normalized ratio, formally known as PT or prothrombin time, an indication of blood clotting speed), albumin and bilirubin levels. Albumin is a blood protein produced by the liver that plays a role in maintaining normal blood volume. Bilirubin is a pigment that is often present in the blood of people with liver inflammation; high bilirubin levels result in jaundice. Many factors, such as the use of medications and alcohol, can cause abnormal lab results. Before drawing your own conclusions about the meaning of a test result, check with a healthcare provider.
This test is an alternative to the liver biopsy to assess the level of liver damage. The Fibroscan is usually combined with other liver biochemical blood tests to better gauge liver damage. The Fibroscan is replacing the liver biopsy since it is a painless procedure unlike the liver biopsy and there is not a risk of complications.
Liver biopsies are done to evaluate the severity of inflammation, the amount of fibrosis or scarring, and general health of the liver. The most common procedure is called a percutaneous (through the skin) liver biopsy, in which the skin and muscle near the liver are numbed and a needle is quickly inserted into the liver to draw out a specimen. Many people fear this procedure, but complications are rare. If you are anxious, ask your physician for a mild tranquilizer prior to your biopsy and for pain medication afterward.
Experimental Noninvasive Fibrosis Tests:
In recent years researchers have developed several noninvasive methods of assessing fibrosis, in an effort to avoid the discomfort and expense of repeat biopsies. Experts have evaluated the accuracy of several combinations of biomarkers including APRI, Fib-4, Forns index, and FibroTest. Noninvasive methods are reasonably accurate in providing information about the amount of liver damage.
Self-Help Tips: Medical History
- List your illnesses and surgeries. Start with the most recent and work backward.
- Try to list only the conditions, diseases, or surgeries that are important for your provider to know.
- Be honest—your provider cannot advise and guide you if you are hiding information. Many people feel like they will be judged if they report that they smoke, drink or take drugs. However, it is important for your provider to know about these in order to guide you and keep you healthy. Be truthful about your feelings. If you are concerned that you might get lectured, talk about it with your provider.
- If possible, review your medical history and records once a month and thoroughly at least once a year.