The website FiveThirtyEight recently turned to a group of testing experts to discuss factors that can affect the reliability of COVID-19 tests and when to be wary of a negative test result.
One of those experts was Bobbi Pritt, M.D., chair of Mayo Clinic's Division of Clinical Microbiology. She noted that test timing is key to getting an accurate result, as testing too soon or too late both can increase the odds of a false negative.
Dr. Pritt explained that the way a COVID-19 test is conducted can contribute to a false negative result, too. If a test doesn't reach the part of the body where the virus is concentrated, for example, it's unlikely to detect an infection. "The gold standard is still the nasal pharynx, several inches up your nose. The amount of virus is higher there than in the tip," Dr. Pritt says.
The article also reviewed differences in reliability between PCR tests and rapid tests, as well as how testing needs to be coupled with quarantining, social distancing and other prevention strategies, such as wearing a mask, to ensure the best protection against spreading COVID-19.