Together with the National Institutes for Health (NIH) and the University of Massachusetts Chan Medical School, the FDA designed a study to test the performance of at-home COVID-19 rapid tests. The study found that symptomatic people who took two rapid tests at least 48 hours apart were able to detect over 90% of COVID infections. Meanwhile, asymptomatic people who tested three times at 48-hour intervals were able to accurately detect COVID 79% of the time.
Their findings were posted on the medRxiv preprint server.
Serial testing is recommended for everyone, regardless of age, vaccination status, or risk of hospitalization. The FDA guidance is applicable to all since it is about the function and timing of the test, not an individual’s circumstances, Irfan Hafiz, MD, chief medical officer and infectious diseases specialist at Northwestern Medicine McHenry Hospital, told Verywell.
Why Wait?
Waiting 48 hours before testing again helps eliminate the chances of getting a false negative due to testing too early, Hafiz said.
If you’re still concerned about COVID-19 after getting your second or third negative test result (especially if you’re experiencing COVID symptoms), consider getting a PCR test, which is more sensitive and accurate.
Hafiz added that the new guidance from the FDA is likely due to a combination of factors, including the widespread availability of home testing, which makes serial testing more realistic than previously in the pandemic. Households can now order a third round of free at-home tests through the U.S. Postal Service.
Serial testing is helpful because people generally don’t know when they are most infectious. Your test results don’t depend on symptoms or when you feel the sickest, but on your viral load. According to Maria Laura Gennaro, MD, professor of medicine and epidemiology at Rutgers New Jersey Medical School, it can be especially hard to pinpoint when an asymptomatic person is infectious without multiple rounds of testing.
Despite all this talk of false negatives, Gennaro said COVID isn’t getting any better at becoming undetectable if people take the time to test correctly.
“The Omicron variants do not evade the tests,” she told Verywell.
The U.S. is currently gearing up for the distribution of bivalent COVID-19 boosters this coming fall or winter to increase protection against the Omicron variant. The guidance about serial testing probably won’t change after people get these boosters, Hafiz said.
The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.
