LOS ANGELES (CNS) — The Los Angeles County Department of Health Services will discontinue the use of Curative COVID-19 PCR tests at its pop-up testing sites this week following a federal warning about the potential for false-negative results, but the tests will still be used at Los Angeles city testing sites.

The county announced the change Sunday night, saying the decision was made in response to a recent U.S. Food and Drug Administration alert regarding the possibility of false negative results.

Curative, a diagnostics company based in San Dimas, provided a limited number of tests at county-supported pop-up testing sites beginning in mid-December. Between December 13 and January 2, a total of 24,241 Curative tests were administered, making up about 10% of all COVID-19 tests at county-supported test sites during that time.

The Curative tests will be replaced with Fulgent Genetics tests.

The FDA warning stressed that the Curative test must be administered in accordance with its authorized use -- which limits it to use on people who are showing symptoms of COVID-19. Testing in Los Angeles is open to people regardless of whether they are showing symptoms.

Mayor Eric Garcetti last week defended the use of the Curative tests at city-operated testing sites, saying administering them on asymptomatic people has allowed the city catch the virus in 92,000 people who would have gone undetected otherwise. He said the city has no plans to drop the Curative tests.

"One-third of the tests that we've tested and found positive are asymptomatic people, and 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," Garcetti said.

"The choice is whether we find those 92,000 or not. It's not like there's some other tests that FDA says is better or that's working better on asymptomatic (people)," he said. "I'd rather do it and continue to push forward with finding those tens of thousands of people that every single month we are finding who are asymptomatic."

Garcetti and county health officials last week stressed that no test is perfect, and the county Department of Health Services reiterated that assertion Sunday, noting that "all COVID-19 tests have a risk of false negative results." That means a person may test negative despite having the disease because the results are sensitive to how well the sample was collected and the concentration of viral RNA in it.

There is no reliable way to detect early infection, meaning that infection often spreads before symptoms have time to develop. Nevertheless, PCR tests — including the Curative test — remain better at detecting disease than some other tests, including rapid tests.

DHS reminded people to follow public health guidance to protect themselves and others by staying home whenever possible, wearing a face covering over the nose and mouth, avoiding gatherings and frequent hand washing.

Curative has also defended its test. The company issued a statement last week saying the 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."

Company officials said they remain committed to following all federal regulations and to ensuring its tests "meet or exceed our customers' expectations."

Curative on Sunday provided data that it says shows that the company's tests detect on average more COVID cases than other testing performed in the state. Company co-founder/CEO Fred Turner said in a statement, "We are confident in our data and we are working with the FDA closely on the matter. Testing sensitivity and accuracy on behalf of our patients is at the heart of our work."