When a person is tested for hepatitis C, there are two possible tests that can be taken.
The first is called an enzyme-linked immunosorbent assay (ELISA) test. When the body becomes infected with the hepatitis C virus, it begins to produce antibodies. These antibodies are in reaction to the virus, and they are the body’s way of fighting the virus. The ELISA test looks for those antibodies. This test is based on the belief that, if the antibodies are there, the body is fighting the hepatitis C virus, and thus a positive antibodies test means that your body has the hepatitis C virus.
The second test is a hepatitis C RNA test, which is a blood test that actually seeks out and measures whether there is prevalence of the hepatitis C virus present. Generally, your medical care provider will give you an ELISA test. This is because the ELISA test is far less expensive. Most likely, you will first be given an ELISA test and, if that test is positive, you may be given an RNA test to confirm the original positive result.
Is it possible to get a false positive? Why?
It is possible to receive a false positive result.
Initially, you are likely given the ELISA test, which is looking for the antibodies that interact with the hepatitis C virus. The general belief is that this test will only be positive and the antibodies will only exist if there is a hepatitis C virus present. However, sometimes there are other reasons why the test can be positive.
Approximately 25% of people who at one point had the hepatitis C virus in their bodies will rid themselves of the virus on their own. The person might not even know that their body is doing this while the process is happening. However, if that person takes the ELISA test after this has happened, there will be antibodies present, but there will not be a hepatitis C virus anymore.
In addition, the body sometimes gets confused. As a general rule, when the body experiences an illness or foreign body (such as an ear or body piercing or an implant in the chin, nose, breasts, or elsewhere), the body creates antibodies in order to fight against this foreign internal “intruder.” However, sometimes, the antibodies are not specific to the exact intruder. Sometimes, those non-specific antibodies can lead to an ELISA test reading that is it positive, though the antibodies that cause the positive reading are actually not battling hepatitis C but rather another kind of illness.
Is it possible to get a false negative? Why?
As previously discussed, the first test that is given to someone who questions their hepatitis C status is the ELISA test, which looks for antibodies in the body.
When a hepatitis C (hep C) infection is brand new, the human body has not yet gathered antibodies to fight that infection. This means that, if the test is performed too early, an ELISA test will give a negative result, because there are not yet enough antibodies present – not because there is no hep C virus.
Unfortunately, many receive a negative result and choose not to get tested for a long period of time, continuing to carry the virus (and possibly transmit it to others) without realizing it.
In addition, some bodies can be so immunocompromised (due to low immune systems or the presence of other illnesses) that their bodies may not be able to make enough antibodies to provide a positive ELISA test.
How do I know if I should trust the results of my test?
In most cases, if a person tests positive for hepatitis C via an ELISA test, they will be given an RNA test to confirm the results.
Since the RNA test measures the actual virus, if you receive positive results on both tests, it is almost certainly an indication that you have hepatitis C in your body.
If you test negative for hepatitis C using the ELISA test method, it is certainly worth re-testing one to three months later, and on a regular basis if you are acting in ways that put you at risk.
It is important to note that the best chance for minimizing permanent damage due to hepatitis C is to become aware of the virus as quickly as possible and to seek treatment immediately.
In many bodies, there are no symptoms of being hepatitis C positive and in others, the symptoms are not present until there has been intense damage done. If you are a person who engages in risky activities, the CDC and other major medical organizations recommend regular testing in order to provide you with the best possible chance of catching an infection early.
Cdc.gov,. "HCV Faqs For Health Professionals | Division Of Viral Hepatitis | CDC". N.p., 2016. Web. 28 Feb. 2016.