Hepatitis C can present as either an acute or a chronic infection. Testing for hepatitis C is usually straightforward. However, testing for hepatitis C needs to be done at a certain time to be fully effective.
The window period for hepatitis C is usually 6-10 weeks following the initial exposure to the hepatitis C virus. During this window period, antibodies against the hepatitis C virus develop and multiply in number. When tested during the window period of hepatitis C, the tests may return a false negative result as the number of antibodies developed may not be enough to be detected. Successful testing for hepatitis C can be done after the window period. An anti-HCV antibody test is highly specific and sensitive when done 12 weeks after the initial exposure to the hepatitis C virus.
Since the development of antibodies is a highly personalized response, the window period may differ in different individuals. For example, the maximum yield of anti-HCV antibodies has been noticed at around six months following the initial exposure in many individuals. However, this maximum yield may take up to 9 months to develop in other individuals.
HOW LONG BEFORE I CAN BE TESTED FOR HEPATITIS C AFTER EXPOSURE?
While the blood tests used for diagnosing hepatitis C are accurate, they still need a little bit of time before they can yield accurate results. This is because, like most infections, hepatitis C has a window period as well. This window period is the time between the initial exposure and the seroconversion of a patient, i.e., the development of antibodies against the hepatitis C virus or HCV.
Until seroconversion has taken place in an individual, blood tests for hepatitis C cannot yield accurate results. In fact, when blood tests are employed during or before the window period, they often yield what is known as false-negative results. This is because the number of antibodies is still too low in the blood to be accurately detected by the testing kit. These false-negative test results are problematic as they may lead to a missed or a wrong diagnosis.
The window period in most individuals lasts for about 4 to 10 weeks from the initial exposure to HCV. So, in theory, a person should have developed a detectable amount of antibodies after ten weeks. However, it takes even longer for patients to develop the maximum antibodies yield.
The best results with the anti-HCV antibody testing are received when patients are tested for antibodies about six months after the time of initial exposure. This is because it takes about six months for most patients to develop the maximum number of antibodies against HCV. However, it may take even longer for some patients to develop the maximum antibodies yield.
The CDC guidelines also recommend anti-HCV antibody testing six months after the initial exposure.
CAN THE BLOOD TEST FOR HEPATITIS C YIELD FALSE RESULTS?
As is evident from the information above, blood tests rely on developing specific parameters in a patient's blood. When these tests are used at the wrong time, for example, during or before the window period, false-negative results can be obtained.
Similarly, the anti-HCV antibody test can also return false-positive results under specific conditions. Sometimes, concurrent auto-immune disorders such as Rheumatoid Arthritis can return a positive HCV antibody test.
WHAT HAPPENS IF A BLOOD TEST FOR HEPATITIS C IS FALSE?
A false blood test for hepatitis C can have devastating consequences if left unchecked.
A false-negative test result can cause a missed or a wrong diagnosis. A missed diagnosis is troublesome because the person's condition worsens, and a false-negative result already rules out the only actual cause.
A false-positive test result can be troublesome and can induce unwarranted anxiety in a patient. Consider hearing the news that you have cancer when you don't believe in reality. A false-positive test result also allows for a barrage of (often) expensive confirmation tests to follow. Therefore, false test results must be dealt with appropriately.
Fortunately, the medical diagnosis algorithm in a modern healthcare setting allows for the recalibration of these false test results. The possibility of a false test result, for example, a false-negative hepatitis C test result, is eliminated through a repeat procedure. Moreover, adequate care is taken only to employ tests when they are most effective.
IS THERE A WAY TO DIAGNOSE HEPATITIS C SOONER?
While the anti-HCV antibody test is the most common initial test when a diagnosis of hepatitis C is suspected, other tests are available. Another blood test, the HCV RNA test, is a much more direct and faster approach to reaching the diagnosis of hepatitis C.
The HCV RNA test detects and quantifies the viral RNA of the hepatitis C virus in a human’s blood. The detection of RNA and its quantification provides an accurate measure of a person's viral load.
A person's viral load is a direct measure of the severity of their disease. Higher viral loads indicate a worse disease state and a poor prognosis, while lower viral loads indicate a clinically-better outcome for the patient.
The HCV RNA test for hepatitis C is also a much faster test than the anti-HCV antibody test, as it can return an accurate result in as little as two weeks following the initial exposure to HCV.
WILL I HAVE LIFELONG IMMUNITY AGAINST HCV AFTER EXPOSURE?
Unlike many viral illnesses, getting infected with the hepatitis C virus once does not confer lifelong immunity against the virus. While re-infections with hepatitis C virus following successful treatment of a previous episode are rare, they are not impossible.
Moreover, getting infected with hepatitis C also does not protect a person against future infections with other hepatitis viruses, such as hepatitis A and B viruses. Viral hepatitis is always a possibility as long as you have active risk factors in your daily life.
The only way to protect yourself from viral hepatitis is to get immunized against the virus. While hepatitis A and B viruses have active vaccines against them, the hepatitis C virus is still without an effective vaccine. Therefore, the only way to protect yourself from ever acquiring an HCV infection is to eliminate the risk factors from your daily life.