PCR test sampling can be flawed due to difficulty obtaining adequate nasal samples, potentially causing false negatives.

“5. Sampling is never flawless either. Swabbing for 10 seconds in the far recesses of the nose where the virus likes to incubate is painful and difficult. It’s easy to give up. #flawedtests Someone whose tests failed could later come back positive if the sampler knows how to get a good sample.”