Window Period

Chlamydia screening smear test
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What is the Window Period?

The window period can sort of be thought of as an STD test waiting period. After you are exposed to a disease and become infected,  you won't test positive right away. Instead, there is generally a length of time before you will test positive for the disease. That period is known as the window period or the STD testing window. It's different from the incubation period, which is the time that passes between being exposed to a disease and starting to experience symptoms.

How long it takes to test positive for a disease such as an STD depends on a number of factors. Things affecting the length of the STD testing window include:

  1. What exactly the test is looking for. Some tests look for the pathogen that causes the disease,. Other tests look for your immune response to the pathogen. In general, the window period is shorter for the first type of test. 
     
  2. The specific test that is being done. For example, a DNA amplification test that looks directly for the organism would usually be able to detect a an infection more quickly than an antibody based test that needs to wait for an immune response. DNA amplification can also find lower quantities of an organism than direct testing. Direct testing options include things like bacterial or viral culture
     
  3. The health of your immune system and whether you have been exposed to a similar infection before. These factors affect how quickly you will make antibodies after infection. 

    Understanding that there's an STD testing window, where results are not accurate, is important. It means that, if you are concerned that you might have been exposed to a particular STD, you need to talk to your doctor. It is very important to discuss when that exposure might have happened. Then your doctor will be able to give you a general idea of whether or not you have passed the window period for STD testing .

    If not, she may tell you that it would be better to wait and get tested (or re-tested) at a later date.

    Testing while you are still inside the window period could lead to inconsistent test results. It could also cause a misleadingly false negative test. This is why STD screening may not provide an accurate reflection of your health status when you have had unprotected sex relatively recently. It takes a while before tests to become accurate. Unfortunately, that means that you just have to be careful while you wait.

    STD Testing Window Period Examples

    People who may have been exposed to HIV are generally told to retest at least once . The recommendation is that they come back six months to a year after the presumed exposure. At this time, the window period will have passed for the vast majority of HIV infections/ Therefore, negative tests will almost be certainly true negatives instead of false negatives -- where the person hasn't had enough time to seroconvert.

    During acute HIV, the virus is replicating but the body has yet to form antibodies.

    In this case, a clinician can specifically test for the virus itself to assess for acute HIV. There are also specific tests that are suitable for detecting recent HIV infections (less than 170 days old),. However, these tests are not widely used outside of research settings. As such if you think you have had a recent HIV exposure, it's better to be safe than sorry. Consistently practicing safe sex can protect your partners. Talking to your doctor, and scheduling appropriate testing, can protect you . After all, early HIV treatment can keep you in good health for a very long time. Appropriate treatment can make HIV into a chronic disease rather than a terrifying life sentence. It can also keep your partner(s) safe through the principles of treatment as prevention. The benefits of treatment are also there with a late diagnosis, but they work even better with an early one. 

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