Molecular assays available for detecting influenza virus infection include rapid molecular assays, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), and other nucleic acid amplification tests. These tests can detect influenza viral RNA or nucleic acids in respiratory specimens with high sensitivity and high specificity. Notably, the detection of influenza viral RNA or nucleic acids by molecular assays does not necessarily indicate detection of viable virus or on-going influenza viral replication. Available FDA-cleared molecular assays are listed in Table 3.

For clinicians about the the advantages and disadvantages of rapid influenza diagnostic tests RIDTs, their use in clinical decision-making and how to interpret results – CDC
— Read on www.cdc.gov/flu/professionals/diagnosis/clinician_guidance_ridt.htm