The last thing you want when being tested for Hepatitis C (HCV) is a false-positive result. HCV is a viral infection that affects the liver. Unfortunately, false positives do occur. Keep reading to learn why this happens and what you can do about it.
What Is a False Positive?
A false-positive test is one in which the result indicates you have a disease or condition when you actually don’t.
There are two blood tests used to diagnose hepatitis C. The enzyme-linked immunosorbent assay (ELISA) screen is often the first test performed. It tests for HCV antibodies that the body has produced in response to the infection. One drawback is that the ELISA screen can’t differentiate between an active infection versus a chronic or previously acquired infection. The HCV RNA test is also an option. The RNA test looks for the virus in the bloodstream. This test is more expensive and is usually conducted to verify a positive ELISA test.
A positive ELISA test doesn’t necessarily mean 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 an RNA test.
People who have recovered from hepatitis C on their own may also get a false-positive ELISA 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 ELISA test, future ELISA 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 if you’ve contracted the virus.
How Common Is a False-Positive Result?
The frequency of false-positive results is hard to determine since few good quality studies have been done. In one study of 1,090 people in the hospital with acute liver disease or suspected hepatitis, the ELISA test had a false positive rate of 3 percent.
The Centers for Disease Control and Prevention (CDC) indicates that the percentage for false positives is much higher. According to the CDC, about 35 percent of people with a low risk of infection, including blood donors, healthcare workers, and active or retired military personnel, receive a false-positive result. In people with compromised immune systems, such as those on hemodialysis, false positives average 15 percent.
The Impact of a False-Positive Hepatitis C Test Result
Hearing you’ve had a positive hepatitis C test may cause anxiety. Even if you’re told more tests are necessary to confirm the diagnosis, waiting for a definitive answer is tough and may cause extreme anxiety.
It’s difficult to measure the impact of a false-positive test since it varies among individuals, but one review published in the Journal of General Internal Medicine indicates that it negatively impacts quality of life. The review also concluded that a false-positive result can lead to unnecessary costs and additional tests, as well as decreased trust in healthcare providers.
Steps to Take After a Positive Hepatitis C Test Result
When you receive a false-positive result, you may be unsure if it’s a true false positive. You may still be unsure even if you’re 100 percent certain that you’ve never been exposed to the virus. Talk with your doctor about getting a second test, such as an RNA test, to confirm whether or not 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 have not yet built up detectable antibodies. People with suppressed immune systems may also get a false negative because their immune systems aren’t working well enough to respond to the test.
If you get a positive Hepatitis C test, it’s possible the results may be wrong. If it turns out that you do have the virus, it may clear up on its own. Treatment can also keep the infection under control. A positive outlook is a great weapon to help you battle the virus and win.