While the decision affects pop-up sites administered by the county, it does not for now change the status of other sites operated by the city of Los Angeles, such as Dodger Stadium, as well as those run by other organizations.
The U.S. Food and Drug Administration recently issued an alert about Curative's COVID-19 test, saying that particularly if the test is not performed as authorized "there is a greater risk that the results of the test may not be accurate."
Experts believe user error is likely to blame in the reported false negative results, as the Curative test allowed people to self-swab. L.A> County's health department said all COVID-19 tests carry a risk of false negative results, but the Curative tests appear to be higher than most.
Curative's test is used in sites throughout Los Angeles. The county says about 10% of the 24,000 tests performed at county pop-up testing sites since mid-December were Curative tests.
"The curative platform, just like the antigen platforms, are very specific tests -- meaning if its positive, it's positive," said Dr. Anthony Cardillo ER specialist and CEO of Mend Urgent Care. "However, there's a lot of false negative data coming out now, meaning if you get a negative result, it may not be a true negative."
The county said Sunday as a precaution, it will stop using the Curative test at county-supported sites and will instead use a test by Fulgent Genetics.
In addition to the county pop-up testing sites, Curative's website indicates the company is involved in running at least three dozen testing sites within the city of Los Angeles, including Dodger Stadium. It was not immediately clear if the city of Los Angeles also plans to discontinue its partnership with the company.
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Mayor Eric Garcetti last week defended the Curative tests, saying administering them on asymptomatic people has allowed the city catch the virus in 92,000 people who would have gone undetected otherwise.
"The proof is that we've had a third of people, nearly 100,000 people who would have gone undiagnosed, that we were able to catch because of this test -- and it has helped us predict those surges in hospitalizations and deaths as a result,'' Garcetti said. "I'm not going to ever apologize because there was, I think, a lot of debate about whether asymptomatic people should be tested or not."
Curative, a diagnostic firm based in San Dimas, has defended its tests, issuing a statement recently: "Curative'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,'' according to a statement from the company.
"The test performance and labeling, however, have not changed, nor has the company observed any changes in test performance. We have been working with the agency to address their concerns and these limitations, and we will continue to work interactively with FDA through the Emergency Use Authorization.''
Curative has administered more than 11 million tests nationwide, including in other major cities like San Francisco, Chicago, Houston and Atlanta.
County officials also noted any test may carry some risk of a false negative.
"All COVID-19 tests have a risk of false negative results, which means that you may test negative when you actually have COVID-19," the county noted.
"That is because the sensitivity depends on how well the sample was collected and the concentration of viral RNA in the sample. There is no reliable way to detect early infection, meaning that infection often spreads before symptoms develop. Nevertheless, PCR tests, including the Curative test, remain better at detecting disease than other tests, including rapid tests."