As COVID-19 testing becomes more widely available, it’s vital that health care providers and public health officials understand its limits and the impact false results can have on efforts to curb the pandemic.

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A special article published in Mayo Clinic Proceedings calls attention to the risk posed by overreliance on COVID-19 testing to make clinical and public health decisions. The sensitivity of reverse transcriptase-polymerase chain reaction (RT-PCR) testing and overall test performance characteristics have not been reported clearly or consistently in medical literature, the article says.
As a result, health care officials should expect a “less visible second wave of infection from people with false-negative test results,” says Priya Sampathkumar, M.D., an infectious diseases specialist at Mayo Clinic and a study co-author.
“RT-PCR testing is most useful when it is positive,” says Dr. Sampathkumar. “It is less useful in ruling out COVID-19. A negative test often does not mean the person does not have the disease, and test results need to be considered in the context of patient characteristics and exposure.”
Even with test sensitivity values as high as 90%, the magnitude of risk from false test results will be substantial as the number of people tested grows. “In California, estimates say the rate of COVID-19 infection may exceed 50% by mid-May 2020,” she says. “With a population of 40 million people, 2 million false-negative results would be expected in California with comprehensive testing. Even if only 1% of the population was tested, 20,000 false-negative results would be expected.”
Read more at Mayo Clinic
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