Getting Tested for Hepatitis C
Questions? Call 888-443-4372 (HEPC)
- How can people find out if they have hepatitis C?
- What is the window period for hepatitis C?
- What does a positive hepatitis antibody test mean?
- Can you get a false positive hepatitis C test result?
- Are there tests to determine whether or not a person has cleared hepatitis C?
- Are there tests to determine how much liver damage people have?
- What is a genotype test?
Since 1992, antibody tests have been available to determine whether people have been infected with hepatitis C. Today, people can have these tests performed at their doctors' offices. For people with no insurance, there are some clinics that can also perform the tests for free or reduced fees. For people who would like to get tested, it is a good idea to wait between 3 to 6 months from the last time they had a risk of infection before they go in for the test. This is because it takes up to 6 months for people to develop enough antibodies to be detected on a test. However, if someone has had many risks over a long period of time (injection drug users, for example) they may want to go in for a test even if it has been less than 3 to 6 months since their last potential exposure to the virus. If their test is negative, they might want to get retested later.
It is recommended that an individual wait 3 to 6 months after their possible hepatitis C exposure before getting tested. This is referred to as the "window period."
A positive antibody test could mean one of two things. It could mean that a person is infected with hepatitis C and is therefore able to transmit the virus to others. Or it could mean that the person was infected with hepatitis C but has cleared it from his or her body. An antibody test cannot tell anyone which of those two situations applies. Once infected, a person will continue to have hepatitis C antibodies, and therefore will continue to test positive on a hepatitis C screening test. If you test positive for hepatitis C on an antibody test, it is recommended that you get follow-up testing to determine whether you have an active infection.
It is possible to get a false positive test result.. An hepatitis C antibody test detects the presence of antibodies to the virus. The result of this test is usually reported as "positive" (meaning a person has been exposed to hepatitis C) or "negative" (meaning that a persons has not been exposed). However, researchers have found that if a test result is "weakly positive," it may be a false positive. The Centers for Disease Control and Prevention (CDC) have suggested that weakly positive tests be confirmed with another test called a "RIBA" (described below) before being reported.
The hepatitis C recombinant immunoblot assay (RIBA) test is another test that can be done to confirm the presence of hepatitis C antibodies. In most cases, the RIBA test can tell whether the positive hepatitis C antibody test result was due to actual exposure to hepatitis C (positive RIBA result) or represents a false signal (negative RIBA result). However, in a few cases, when the RIBA result is "indeterminate" it cannot make the distinction between a true or false positive antibody result. It is worth noting that, like the hepatitis antibody test, the RIBA test cannot distinguish between a current hepatitis C infection and an infection that the body has cleared.
If someone is at low risk of having hepatitis C (never shared a needle or never had a blood transfusion) and gets a positive antibody test, it is a good idea for that person to ask their doctor whether any confirmatory test was performed to check the initial positive result. If a confirmatory test was not performed then the person may want to request such a test to be sure they are or were infected with hepatitis C.
Yes. If a person has a positive antibody test, they should then have a viral test -- typically called a PCR test. This type of test is looking for the actual virus, rather than the antibodies, and can tell whether there is any hepatitis C in that person's body. If the PCR test is negative, this means that the person has cleared the virus and is no longer infected. If the PCR test is positive, that means that the person still has active hepatitis C.
Once it has been determined that someone has hepatitis C, many tests will likely be performed on a regular basis. These tests, which include liver enzyme (ALT and AST) and viral load tests, are performed periodically to monitor how that person's liver is functioning and how quickly the hepatitis C is replicating. By themselves, those tests do not show whether hepatitis C is causing significant liver damage. Sometimes an ultrasound and/or a liver biopsy is be performed to get a clearer idea of the liver's health. Liver biopsies are generally considered the best available way to determine whether, and to what extent, liver damage has occurred.
Genotypes are strains of a particular virus. We know that there are 6 genotypes for hepatitis C. Genotype 1 is the most common in the U.S.; genotypes 2 and 3 are the most responsive to treatment. It is possible to have more than one genotype. It is useful to have a genotype test before deciding whether to start hepatitis C treatment.