A patient is handed a test kit at a Covid-19 testing site in Panorama City. Photo credit: Los Angeles County
In an unusual move, the Food and Drug Administration issued a warning on Monday about false negative results with Curative’s Covid-19 test results.
Though the Los Angeles-based startup was only founded a year ago, several government entities are currently using its tests. Curative’s oral swab tests are offered at dozens of drive-thru testing sites across Los Angeles, and the county has also tapped the startup to help administer vaccines to nursing home residents and staff.
Curative’s tests are also used by the U.S. Air Force, and by the House and Senate to screen members of Congress for Covid-19, according to Politico.
The FDA did not specify the rate of false negatives for the test or what might be causing them, but specifically pointed out that the test should be conducted as authorized — meaning that healthcare workers must observe patients who swab themselves, and the test should only be used for symptomatic patients.
The agency also advised healthcare providers to “consider retesting your patients using a different test if you suspect an inaccurate result was given recently by the Curative SARS-Cov-2 test.”
The FDA gave an emergency use authorization to Curative in April for its RT-PCR test, used to detect viral RNA for SARS-CoV-2. The test could be used with a nasopharyngeal swab, a nasal swab or an oral swab, allowing for self-collection.
Even though they might be more comfortable than nasopharyngeal swabs, there are still some nuances to mouth swabs. For example, people shouldn’t eat or drink an hour before the test.
According to a small study conducted by Curative, self-collected oral and nasal swabs were nearly as accurate as nasopharyngeal swabs when observed by healthcare workers. But when patients swabbed themselves unobserved, the test’s accuracy fell dramatically.
Of 23 positive cases identified by a nasopharyngeal swab, only 65% were detected when patients collected a saliva sample unobserved. The study included a total of 44 people, both with and without Covid-19 symptoms.
“The data above does not support use of the Curative SARS-CoV-2, for any individuals for self-collected oral fluid samples when not directly observed and directed by a trained healthcare worker during collection and at the site of collection,” the FDA wrote in a summary of the EUA.
Curative did not respond to requests for comment at the time of publication.
