Image from FDA warning about counterfeit COVID-19 tests. April 29, 2022

“The plastic test cassette may have a 2D barcode which differs from the one printed on FDA-authorized Flowflex tests. The counterfeit tests may have a QR code containing square shapes within a square box on 3 corners of the code, as shown below. The FDA-authorized Flowflex tests have a 2D-datamatrix without those three boxes.”