LA using coronavirus test that FDA warns may produce false negatives


Coronavirus test provided daily to tens of thousands of residents of Los Angeles and other parts of California could produce inaccurate results, warning federal officials who could raise questions about the accuracy of the infection data that are shaping the response to the pandemic.

Food and Drug Administration advice warns healthcare providers and patients that the test performed by Curative, a one-year-old Silicon Valley startup that provides oral swab testing at all 10 sites Los Angeles test, has false results, in particular false negatives. ”

To reduce the risk of false negatives, the curative test should only be used on “symptomatic individuals within 14 days of onset of symptoms of COVID-19”, and the swab should be observed and supervised by a professional. health, the FDA said.

The guide, released Monday, repeats instructions the FDA issued when the test first obtained emergency use clearance.

The FDA warning appears to strongly contradict Los Angeles Mayor Eric Garcetti, who in April made coronavirus testing accessible to everyone, regardless of symptoms. In August, Garcetti said he disagreed with guidance from the Centers for Disease Control and Prevention that tests should only be given to symptomatic patients.

The conflicting approaches raise new questions about the accuracy of the city’s reported COVID-19 positivity rates, including whether the false negatives gave people the mistaken assumption that they could ignore public health advice and come together with others outside their households, contributing to a record level of community spread.

Curative, founded by a 25-year-old British businessman, has administered more than 11 million tests across the country, including in other major cities such as Chicago, San Francisco, Houston, Atlanta, Miami and Seattle. The company has a $ 42 million contract to perform tests at U.S. military treatment facilities and is also testing members of Congress, including those who do not have symptoms.

Unlike nasal swab tests, which must be administered by a healthcare professional deep into a patient’s nose, the curative test is an oral swab that can be self-administered. Patients should cough three times, rub the spit in their mouth, and then rub a cotton swab around their gums, cheeks, and tongue.

The Times reported in April that while the Curative process is much more comfortable than that of nasal swab testing and makes testing much more widely available, it is not the FDA recommended method and may be less accurate.

Los Angeles County halted Curative’s oral swab test at its testing sites in June. Public health director Barbara Ferrer said at the time that nasal tests produced fewer false negatives.

Dr Clemens Hong, who oversees coronavirus testing for LA County, said in an email that the county is aware of the FDA guidelines and “is reviewing and evaluating the results of clinical studies.” He said any type of oral swab test poses a risk of false negatives because the results are based on the correct collection of the saliva sample and the viral load it contains.

Curative is still processing a “limited number” of tests at county-supported pop-up testing sites, Hong said.

The city continues to administer the curative oral swab test at 10 drive-through and walk-in testing sites, including a massive facility at Dodger Stadium that processes thousands of tests per day.

When the county stopped using curative testing, Garcetti spokesman Alex Comisar said Los Angeles was “confident in curative test kits and lab work.”

Since the end of March, more than 3.37 million coronavirus tests have been administered at city test sites since the start of the pandemic, according to city data. Many of these tests were treated by Curative.

A representative from Curative 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 warnings, precautions and specific limitations that the FDA reiterated in the safety communication. However, the test performance and labeling did not change and the company did not observe any change in the test performance. “

The Curative study conducted to validate its test ruled out asymptomatic patients, and the company told the FDA in its emergency clearance request that the test is “limited to patients with symptoms of COVID-19.” .

When the FDA issued emergency clearance for the Curative test in April, it specifically authorized testing of samples “from individuals suspected of COVID-19 by their health care provider.”

FDA guidelines caution that curative testing should be “directly observed and supervised during the specimen collection process by a trained health care worker at the specimen collection site.”

At Dodger Stadium, patients administer the test on themselves inside their cars. A video showing the correct method of swab administration plays on massive screens at the testing site, and the bag with the testing supplies – which is passed through the car window – also contains instructions.

Curative is one of dozens of companies that expedited a coronavirus test and obtained emergency clearance from the FDA after the agency announced in late February that it was removing regulatory hurdles.

Companies with emergency clearance are not allowed to promote their tests as “safe or effective” for virus detection. The policy saves companies from having to comply with approval guidelines which can take up to two years.

Times editors Soumya Karlamangla and Melody Peterson contributed to this report.

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