Covid-19: The Dilemma of When and How Often to Test
The guidelines released have been nothing short of confusing to pretty much everyone. Covid-19 is here and it is spreading like wildfire through our community. So, what should you do if you are exposed to someone with Corona Virus? Experts agree that the first thing you should do is quarantine yourself and assess your timeline. For the most accurate results, testing should occur 3-7 days after the exposure. If you test too soon, you may get a negative result because the virus has not yet replicated in your system. And, since you should quarantine for the full 10-14 days from the exposure regardless of your test results, there is little harm in waiting a few days to test. Now, if you develop symptoms earlier, testing would be advised to either confirm or rule out Covid-19 as the cause of those symptoms.
In the case of known exposure or symptoms present, the test should be an RT-PCR test. This type of test can either be a lab send out or a rapid test. Most are done via nasal or nasopharyngeal swab, but there are also saliva based PCR tests.
What if your test comes back positive? Should you test after 14 days? Most experts say no. The problem with re-testing after a positive is that many people retain a portion of the viral RNA in their system for long periods of time (think glitter --- you clean it all up, but somehow two weeks later you still find pieces of it in your living room), AFTER the infectious (i.e. contagious) period has expired. The PCR tests are highly sensitive and will pick up that portion of the virus causing the result to be positive, when in actuality, you have passed the infectious period. The difficulty here is that some employers have policies that require you to have a negative test to return to work (a perfectly reasonable policy). So, while re-testing isn't recommended, you may need to do so to comply with your company's policies.