COVID-19 PCR tests have served as a crucial tool for identifying positive cases and controlling spread during this pandemic.
But the U.S. Centers for Disease Control and Prevention (CDC) recently alerted labs nationwide that a PCR test for SARS-CoV-2 should be phased out by the end of the year.
Claims in several viral posts that spread online following the announcement misrepresented the reasoning for the move, stating it meant the CDC and the FDA were admitting PCR tests do not work and could not differentiate between the COVID and flu viruses.
One Facebook post quoting the lab directive added, “Translation: They’ve been adding flu cases to Covid cases when using that test,” while another included an altered screengrab of the actual CDC directive.
This widely shared post on Instagram went so far as to say the PCR test had “failed its full review,” and emergency use authorization had been “revoked.”
Is the CDC discontinuing this test because it’s inaccurate and can’t tell the difference between the COVID-19 and flu viruses?
No, the CDC is not discontinuing a test because it’s inaccurate. Instead, the agency is no long requesting Emergency Use Authorization approval for a particular PCR test developed early in the pandemic because it can only detect coronavirus. Labs are encouraged to utilize newer versions that can test for both.
WHAT WE FOUND
The alert issued in July said the agency is withdrawing its emergency use authorization request for the polymerase chain reaction, or PCR, test to detect SARS-CoV-2 that’s been in use since the start of the pandemic.
PCR testing, which utilizes a nasal swab, is widely considered the most accurate currently available for detecting COVID-19. But this particular test is only capable of detecting the COVID-19 virus.
“It’s important for people to realize that this test was developed in February 2020,” Dr. Harry Heiman said, “a time when many people were racing to develop testing technology for the coronavirus.”
Today there are more than 250 PCR tests approved for use and many, according to Dr. Heba Mostafa, can detect both SARS-CoV-2 and influenza.
In the lab alert issued by the CDC, the agency said it preferred that labs move forward using this so-called “multiplexed method” to test people for multiple viruses at the same time.
That method, reads the CDC alert, “can save both time and resources as we head into influenza season,” which is crucial given symptoms between the two viruses can be so similar, Mostafa said.
“You want a test that up front can tell you if this is COVID or influenza,” she said. “So the best way to do this is to use one test that can give you this quick result right away.”
As for questions about accuracy, the CDC said the decision to discontinue it was not based on the test’s performance.
Mostafa said this particular test was precise when used her own lab, but that was early on in the pandemic.
“I was not really surprised with their justification,” she said. “Because there are too many options and I don’t think many labs are using this [test] right now anyways.”