Los Angeles County health officials said on Sunday they would stop providing a commonly used coronavirus test after federal regulators raised questions about its accuracy.
The decision affects only a small number of county-supported mobile test sites. County health officials had already stopped widespread use of oral smear tests produced by Silicon Valley start-up Curative during the summer because of concerns about many false negatives.
The use of curative oral smear tests at the 10 drive-through test sites in the city of Los Angeles, including the huge facility at Dodger Stadium, were not affected by Sunday’s decision. Mayor Eric Garcetti defended the tests as largely effective and said that moving away from them could lead to fewer people being diagnosed and greater spread of the virus.
Guidance issued last week by the Food and Drug Administration warned healthcare professionals and patients that the test done by Curative carries a “risk of false results, particularly false negative results”.
To reduce the risk of false negatives, the curative test should only be used on “symptomatic individuals within 14 days of the onset of COVID-19 symptoms” and the smear should be observed and directed by a healthcare professional, said the FDA.
Los Angeles has been using the tests since April. Responding to FDA guidance last week, Garcetti strongly supported the tests. Although the curative test is designed to track people who are visibly ill, he added that the tests are also effective in detecting cases in asymptomatic people. He said that about a third of the city’s positive test results – about 92,000 – came from people with no symptoms.
In June, LA County stopped using the Curative oral smear test at its main testing sites. Public health director Barbara Ferrer said at the time that nasal tests produced fewer false negatives.
In mid-December, however, Curative started providing tests at mobile county-supported test sites. Between December 13 and January 2, Curative administered 24,241 tests in these county-supported locations, about 10% of all coronavirus tests administered in those locations during that period, the county’s Department of Health and Human Services said in a statement. on Sunday.
County officials said they were discontinuing the use of curative tests “as a precaution” and would replace them with tests from Fulgent Genetics.
Health officials say any type of test is at risk of false negatives, as the results depend on the correct collection of the saliva sample and the viral load it can contain.
“There is no reliable way to detect the infection early, which means that the infection usually spreads before symptoms develop,” the statement said.
However, county officials said curative tests remain better at detecting disease than other tests, including rapid tests.
Curative, founded by a 25-year-old British businessman a year ago, administered more than 11 million tests across the country, including in other major cities like Chicago, San Francisco, Houston, Atlanta, Miami and Seattle. The company maintains a $ 42 million contract to conduct tests at U.S. military treatment facilities and also test members of Congress, including those who have no symptoms.
Unlike nasal smear tests, which must be administered by a medical professional to the patient’s nose, the Curative test is an oral smear that can be self-administered. Patients should cough three times, spit in the mouth, and then rub a cotton swab around the gums, cheeks and tongue.
Following FDA guidance issued last week, a Curative representative said in a statement that the company’s test “has been validated and is being offered during the pandemic under an Emergency Use Authorization and is labeled with specific warnings, precautions and limitations. that the FDA reiterated in the Safety Communication. Test performance and labeling, however, did not change, nor did the company observe any changes in test performance. ”
The Curative study conducted to validate its test excluded patients who were asymptomatic, and the company told the FDA, in its request for emergency clearance, that the test is “limited to patients with symptoms of COVID-19”.
When the FDA issued an emergency use authorization for the Curative test in April, it specifically authorized testing for samples “of individuals suspected of COVID-19 by their health care provider”.