Hepatitis C Virus Tests
Hepatitis C virus (HCV) test is a blood test that looks for the genetic material (RNA) of the virus that causes hepatitis or for the proteins (antibodies) the body makes against HCV. These proteins will be present in your blood if you have a hepatitis C infection now or have had one in the past. It is important to identify the type of hepatitis virus causing the infection, to prevent its spread and choose the proper treatment.
HCV is spread through infected blood.
- Anti-HCV antibody tests look for antibodies to HCV in the blood, indicating an HCV infection has occurred. This test cannot tell the difference between an acute or long-term (chronic) infection. The enzyme immunoassay (EIA) may be the first test done to detect anti-HCV antibodies.
- HCV RIBA is another test that detects antibodies to HCV. This test can tell whether a positive result was caused by an actual HCV infection or whether the result was a false-positive. This test may be done to double-check a positive EIA test result.
- HCV genetic
material (RNA) testing uses polymerase chain reaction (PCR) to identify an
active hepatitis C infection. The RNA can be found in a person's blood within 2 weeks after exposure to the virus. HCV RNA testing may be done to
double-check a positive result on an HCV antibody test, measure the level of
virus in the blood (called viral load), or show how well a person with HCV is
responding to treatment.
- HCV quantitative test (also called viral load) is often used before and during treatment to find out how long treatment needs to be given and to check how well treatment is working.
- HCV viral genotyping is used to find out which genotype of the HCV virus is present. HCV has six genotypes, and some are easier to treat than others.
There is no vaccine available to prevent hepatitis C.
Why It Is Done
Hepatitis C virus testing is done to:
- Find out if a hepatitis C infection is the cause of abnormal liver function tests.
- Screen people (such as doctors, dentists, and nurses) who have an increased chance of getting or spreading a hepatitis C infection.
- Screen potential blood donors and donor organs to prevent the spread of hepatitis C.
- Screen people born from 1945 to 1975. People in this age group are more likely to have hepatitis C and not know it.
- Identify the type of hepatitis C virus causing the infection.
How To Prepare
You do not need to do anything before you have this test.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form (What is a PDF document?).
How It Is Done
The health professional taking a sample of your blood will:
- Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
- Clean the needle site with alcohol.
- Put the needle into the vein. More than one needle stick may be needed.
- Attach a tube to the needle to fill it with blood.
- Remove the band from your arm when enough blood is collected.
- Put a gauze pad or cotton ball over the needle site as the needle is removed.
- Put pressure on the site, and then put on a bandage.
How It Feels
The blood sample is taken from a vein in your arm. An elastic band is wrapped around your upper arm. It may feel tight. You may feel nothing at all from the needle, or you may feel a quick sting or pinch.
There is very little chance of a problem from having a blood sample taken from a vein.
- You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
- In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this.
Results of hepatitis C virus testing that show no infection are called negative. This means that no antibodies against HCV or HCV genetic material was found. Results are usually available in 5 to 7 days.
No hepatitis C antibodies are found.
No hepatitis C genetic material (RNA) is found.
Hepatitis C antibodies are found. A test to detect HCV RNA is needed to determine whether the infection is current or occurred in the past. If HCV RNA is found, genotyping can determine which strain of HCV is causing the infection.
Hepatitis C RNA is detected. This result means a current hepatitis C virus infection.
Hepatitis antibodies can take weeks to develop, so your results may be negative even though you are in the early stage of an infection.
What Affects the Test
Many conditions can change HCV antibody levels. Your doctor will talk with you about any abnormal results that may be related to your symptoms and past health.
Your results may need to be rechecked if you are taking some herbs, supplements, or other alternative medicine products.
What To Think About
- There is no vaccine to prevent infections with the hepatitis C virus.
- All donated blood and organs are tested for hepatitis C before being used.
- Other tests that show how well the liver is working are usually done if your doctor thinks you may have hepatitis C. These may include blood tests for bilirubin, alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase.
- Provinces require that some types of hepatitis infections be reported to the local health unit. The health unit can then send out a warning to other people who may have been infected with the hepatitis virus, such as those who are close contacts of someone who has hepatitis C.
Other Works Consulted
- Centers for Disease Control and Prevention (2003). Guidelines for laboratory testing and result reporting of antibody to hepatitis C virus. MMWR, 52(RR-03): 1-16. Available online: http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5203a1.htm.
- Pagana KD, Pagana TJ (2010). Mosby's Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
- Scott JD, Gretch DR (2007). Molecular diagnostics of hepatitis C virus infection: A systematic review. JAMA, 297(7): 724-732.
Primary Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Brian D. O'Brien, MD - Internal Medicine
Adam Husney, MD - Family Medicine
Kathleen Romito, MD - Family Medicine
Specialist Medical Reviewer W. Thomas London, MD - Hepatology
Current as ofMarch 3, 2017
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