L.A. using coronavirus test that FDA warns may produce false negatives

The coronavirus test being provided daily to tens of thousands of residents in Los Angeles and other parts of California may be producing inaccurate results, according to a warning from federal officials that could raise questions about the accuracy of infection data shaping the pandemic response. The guidance from the Food and Drug Administration warns healthcare providers and patients that the test made by Curative, a year-old Silicon Valley start-up that supplies the oral-swab tests at L.A.'s 10 drive-through testing sites, carries a "risk of false results, particularly false negative results." To reduce the risk of false negatives, the Curative test should be used only on "symptomatic individuals within 14 days of COVID-19 symptom onset," and the swab should be observed and directed by a healthcare worker, the FDA said. The guidance, issued Monday, repeats the instructions that the FDA issued when the test was first granted an emergency-use authorization. The FDA warning appears to sharply contradict Los Angeles Mayor Eric Garcetti, who in April made coronavirus testing available to anyone, regardless of symptoms.