Hepatitis C (HCV) is a viral infection that affects the liver. False positives can occur for a variety of reasons.

Keep reading to learn why this happens and what you can do about it.

A false-positive result means that a test indicated that you have a disease or condition when you actually don’t.

There are two blood tests used to diagnose hepatitis C. The antibody test, also called the anti-HCV test, tests for HCV antibodies that the body has produced in response to the infection.

One drawback is that the anti-HCV test can’t differentiate between an active infection versus a chronic or previously acquired infection.

A positive anti-HCV test doesn’t necessarily mean that you have hepatitis C. Antibodies picked up by the test may have been triggered by an infection other than HCV, leading to a positive result.

This phenomenon is known as cross-reactivity, and it often results in a false positive. The results may be verified through a second blood test.

The hepatitis C viral load test, also called an RNA test, will show whether you have chronic hepatitis C or a false positive.

You may receive a false-positive result if your antibodies are triggered by another infection. People who’ve recovered from hepatitis C on their own may also get a false-positive anti-HCV test result.

In rare cases, lab error leads to a false positive. False-positive results may also occur in newborns who carry HCV antibodies from their mothers.

Once you’ve had one positive anti-HCV test, future anti-HCV tests are also likely to be positive. If you’re exposed to hepatitis C later in life, you should get an RNA test to determine whether you’ve contracted the virus.

False-positive results appear to be common. According to a 2017 report, 22 percent of 479 subjects received a false-positive anti-HCV test.

According to a 2020 report, the rate of false-positive test results among 1,814 reactive serum samples was 10 percent.

When you receive a false-positive result, you may be unsure whether it’s a true false positive. Talk with your doctor about getting a second test, such as an RNA test, to confirm whether you have an infection.

If your RNA test result is negative, you don’t have a current HCV infection. In this scenario, no further steps need to be taken. If your RNA test result is positive, your doctor will advise you on treatment options and how to move forward.

Keep in mind that false-negative results may happen, too. This often occurs in people who are in the early stages of infection and haven’t yet built up detectable antibodies.

People with suppressed immune systems may also get a false negative because their immune systems aren’t working effectively enough to respond to the test.

If you get a positive result on an anti-HCV test, it’s possible that it’s incorrect. A doctor will typically give you a second test to confirm the results.

Treatment can keep the infection under control, so talk with a medical professional about the next steps.

Read this article in Spanish.