Do health care providers say diagnostic tests for the coronavirus result in a high number of false positives?
Health care providers say standard diagnostic tests for the presence of the coronavirus rarely return false positives. False-positive rates from "molecular" tests based on nasal or throat swabs or samples of bodily fluids are "close to zero," meaning a positive result is a reliable indicator of infection, Harvard Medical School says.
False-negative rates, when a test fails to detect an actual infection, have been estimated to range as high as 29%. "A negative result should not give you a false sense of security," MIT's medical center warns.
False negatives add to the challenge of tracking and slowing the spread of the virus. A July 2020 study examining serology test results—which detect past infections—concluded that in the U.S. in spring 2020 there were likely 10 times more actual infections than were reported.
