Analytical comparison of over-the-counter multiplex tests for influenza A, influenza B, and SARS-CoV-2

classification, or 510(k) clearance, limited data are available to inform consumers of their relative performance. We performed a head-to-head benchtop analytical assessment of OTC tests available for purchase from retailers in the United States in the fall of 2025. Contrived specimen dilution panels were prepared from propagated viral stocks of influenza A H1N1pdm09, influenza A H3N2, influenza B (Victoria lineage), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) JN.1 (Omicron variant) in clinical matrix and applied to the swab provided with each kit. Tests were subsequently performed according to the manufacturer's instructions for use, and results were interpreted by two readers blinded to the starting test material. Lower limits at which three of three replicates of test material were detected were within a fourfold dilution for all four viruses and all eight OTC tests evaluated. We found that at low viral concentrations, many OTC tests were interpreted as negative at the start of the stated interpretation window but converted to a positive result by the end of the interpretation window. We conclude that eight OTC tests that are currently readily available to consumers perform similarly in a contrived specimen analytical study, but we recommend that users of OTC lateral flow tests allow for the full incubation time before concluding that a test is truly negative. IMPORTANCE: Our study provides consumers and medical professionals alike with a head-to-head comparison of the available over-the-counter coronavirus disease (COVID)/flu rapid antigen tests through a controlled, systematic evaluation. We also highlight the observation that, at low viral concentrations, many of the tests converted from negative to positive during the designated "interpretation window," resulting in a practical recommendation that consumers should wait for the full incubation time before concluding that a self-test is negative.