Rapid tests for SARS-CoV-2 may have drawbacks under real-world conditions, the New York Times reports.
The Times notes that Quidel's rapid antigen test is authorized for testing people who have COVID-19 symptoms, but it adds that the government has pushed for the use of such tests on asymptomatic people. Researchers from the University of Arizona investigated how Quidel's test performs in such situations and found — in results not yet peer reviewed — the test missed 54 individuals out of 304 people with symptoms who tested positive for SARS-CoV-2 by PCR, of a total 885 symptomatic people tested. However, it missed 13 of the 19 asymptomatic people who tested positive for the virus by PCR out of a total 1,551 asymptomatic people tested, according to the Times.
These findings, study author David Harris from Arizona tells the Times, were expected. He and his colleagues note, the Times adds, that some of the discrepancy between the results could be traced to PCR tests with high cycle threshold values, suggesting the samples might not have had much virus present. Doug Bryant, the president and CEO of Quidel, tells the Times that results highlight the test's ability to identify "people who are infectious."
Still, others advise caution, the Times adds. "The data for the symptomatic group is decent," Jennifer Dien Bard from Children's Hospital Los Angeles tells it. "But to get less than 50 percent in the asymptomatic group? That's worse than flipping a coin."