L.A. County will stop using Curative coronavirus test after concerns from the FDA
Los Angeles County health officials said Sunday they will 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 testing sites. County health officials had already discontinued the broad use of oral swab tests produced by Silicon Valley start-up Curative over the summer because of concerns about too many false negatives.
Testing operations at Dodger Stadium, the largest coronavirus testing site in the U.S., will end Monday, according to the mayor’s office. Officials hope to eventually vaccinate 12,000 people a day there.
The use of Curative oral swab tests at the city of Los Angeles’ drive-through testing sites are unaffected by Sunday’s decision, although Mayor Eric Garcetti’s office said separately that the Dodger Stadium site would be turned into a vaccine distribution center this week, ending testing operations there Monday. Garcetti has defended the tests as broadly 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 from the Food and Drug Administration warned healthcare providers and patients that the test made by Curative 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.
Los Angeles has been using the tests since April. Responding to the FDA guidance last week, Garcetti strongly backed the testing. While the Curative test is designed for screening people who are visibly ill, he added that the tests are also effective at catching cases in people who are asymptomatic. He said that about one-third of the positive test results from the city’s program — about 92,000 — were from people without symptoms.
In June, L.A. County discontinued its use of Curative’s oral swab testing 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 began supplying tests at mobile testing sites supported by the county. Between Dec. 13 and Jan. 2, Curative administered 24,241 tests at these county-supported sites, about 10% of all coronavirus tests administered at such sites during that time frame, the County Department of Health and Human Services said in a statement Sunday.
County officials said they were discontinuing the use of the Curative tests “as a precaution” and would replace them with tests by Fulgent Genetics.
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Health officials said that any type of test poses a risk of false negatives, because the results rely on the correct collection of the saliva sample and the viral load that it may contain.
“There is no reliable way to detect early infection, meaning that infection often spreads before symptoms develop,” the statement said.
Nevertheless, county officials said the 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, has administered more than 11 million tests nationwide, including in other major cities such as Chicago, San Francisco, Houston, Atlanta, Miami and Seattle. The company holds a $42-million contract to perform testing in U.S. military treatment facilities and also tests members of Congress, including those who do not have symptoms.
Unlike nasal swab tests, which must be administered by a medical professional deep into a patient’s nose, the Curative test is an oral swab that can be self-administered. Patients are required to cough three times, swish the spit in their mouths, then rub a cotton swab around their gums, cheeks and tongue.
After the 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 FDA reiterated in the Safety Communication. The test performance and labeling, however, have not changed, nor has the company observed any changes in test performance.”
The study Curative conducted to validate its test excluded patients who were asymptomatic, and the company told the FDA, in its application for emergency authorization, that the test is “limited to patients with symptoms of COVID-19.”
When the FDA issued an emergency use authorization for Curative’s test in April, it specifically authorized the test for samples “from individuals suspected of COVID-19 by their healthcare provider.”
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