To prep for a complicated flu season, FDA greenlights CDC's combined influenza, COVID-19 test

The FDA issued a new emergency authorization to the Centers for Disease Control and Prevention for a combination influenza and COVID-19 diagnostic test—as the U.S. prepares to enter its annual flu season later this year in the midst of a global pandemic.

The test is designed to help tell the difference between patients with one of the two diseases, who may present with similar respiratory symptoms. It’s the third diagnostic authorized by the FDA for this purpose, following panels from Qiagen and BioFire Diagnostics, which also cover additional viruses.

“With just one swab or sample, combination tests can be used to get answers to Americans faster,” FDA Commissioner Stephen Hahn said in an agency statement. “This efficiency can go a long way to providing timely information for those sick with an unknown respiratory ailment.”

Additionally, testing for multiple diseases using a single swab can help reduce the demand for testing supplies, and reduce the risk of exposure to healthcare workers gathering the sample.

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The CDC’s multiplexed assay is designed to spot only the genetic material of the novel coronavirus as well as the influenza A and B viruses, using both swabs and sputum samples. However, negative results should not be used as the sole basis of ruling out an infection, according to the agency (PDF). 

The test is designed to run on Thermo Fisher’s Applied Biosystems 7500 sequencing hardware. The CDC said the kits will be shipped to public health laboratories when production and quality control have been completed.

In the earliest weeks of the coronavirus’ spread through the U.S.—which currently counts nearly 2.9 million cases and 130,000 deaths—the CDC’s first coronavirus diagnostic failed to produce the correct result when one of its three reagents was tested against a certain control. That reagent was later eliminated from the test’s procedure, and the CDC says the kits are still in use. The newer test includes one primer mix and one probe mix.

The FDA said it is encouraging developers to pursue more combination tests before the flu season begins in earnest this fall and winter, and has updated its submission templates for molecular diagnostic Emergency Use Authorizations.