Recently I’ve received quite a few emails from people who had hepatitis C, were successfully treated, but were told that their hep C is back. You could practically feel their distress popping off the page.

However, it didn’t take much detective work on my part to suspect that none of these people had hepatitis C. A few email exchanges and follow up tests confirmed my suspicions. Every single one of these cases showed up because they had new doctors who ordered the recommended hep C screening for baby boomers. The initial  test screens for hepatitis C antibody, and anyone who was ever exposed to hep C would have a positive result. Hepatitis C antibodies don’t go away when people are cured.

Hepatitis C testing can be confusing, and if you don’t understand the results, you may think you have hepatitis C when you actually don’t. So let’s walk through this.

Several tests are used to detect hepatitis C. Assuming that someone was exposed to hepatitis C for at least six months, then a hepatitis C antibody test is performed. If the results are negative, then the person does not have hepatitis C.

If the results are positive, then further testing is needed because a positive hepatitis C antibody test does not mean you have it. This is because 15 percent to 25 percent of those who are exposed to hepatitis C will clear the virus on their own. If you are a woman, you have a 40 percent chance of spontaneously clearing hepatitis C; 19 percent if you are a man. These chances drop if you are significantly older (50+). And if there is any doubt about what spontaneously clearing hepatitis C means, it means your body fought it off naturally, and it isn’t in your body any longer.

So, how do you know if you just have the antibody and not the actual virus? You need a viral load test (aka PCR). The viral load, or HCV RNA, measures the actual virus. The presence of HCV RNA confirms the patient has hepatitis C.

If you have a positive hepatitis C antibody test and a non-detectable viral load, then you do not have hepatitis C—you were exposed and probably cleared it on your own. Unlike measles or mumps, the presence of hepatitis C antibodies does not protect you from future infections.

If the exposure is less than six months, there might not have been time for hepatitis C antibody to form. In this case, if the antibody test is negative, a viral load test needs to be done. If the viral load test is non-detectable, then you do not have hepatitis C. Non-detectable means negative.

Anyone who ever had hepatitis C will still have a positive hepatitis C antibody test. So, doing a hepatitis C antibody test on someone who was cured is a waste of money, effort, and blood. If you and your doctor think you may have a new hep C infection, then a viral load test is a better way to find out. Some doctors will also order a liver panel test, which is cheaper and can help detect liver problems.