TABLE 6

Comparison of Types of Influenza Diagnostic Tests

Testing CategoryMethodInfluenza Viruses DetectedDistinguished Influenza A Virus SubtypesTime to ResultsPerformance
Rapid molecular assayNucleic acid amplificationInfluenza A or B viral RNANo15–30 minHigh sensitivity; high specificity
Rapid influenza diagnostic testAntigen detectionInfluenza A or B virus antigensNo10–15 minLow-to-moderate sensitivity (higher with analyzer devise); high specificity
Direct and indirect immunofluorescence assaysAntigen detectionInfluenza A or B virus antigensNo1–4 hModerate sensitivity; high specificity
Molecular assays (including RT PCR)Nucleic acid amplificationInfluenza A or B viral RNAYes, if subtype primers are used1–8 hHigh sensitivity; high specificity
Multiplex molecular assaysNucleic acid amplificationInfluenza A or B viral RNA; other viral or bacterial targets (RNA or DNA)Yes, if subtype primers are used1–2 hHigh sensitivity; high specificity
Rapid cell culture (shell vial and cell mixtures)Virus isolationInfluenza A or B virusYes1–3 dHigh sensitivity; high specificity
Viral culture (tissue cell culture)Virus isolationInfluenza A or B virusYes3–10 dHigh sensitivity; high specificity
  • Negative results may not be used to rule out influenza. Respiratory tract specimens should be collected as close to illness onset as possible for testing. Clinicians should consult the manufacturer’s package insert for the specific test for the approved respiratory specimen(s). Specificities are generally high (>95%) for all tests compared with RT PCR. FDA-cleared rapid influenza diagnostic tests are Clinical Laboratory Improvement Amendments waived; most FDA-cleared rapid influenza molecular assays are Clinical Laboratory Improvement Amendments waived depending on the specimen. RT, reverse transcriptase. Adapted from Uyeki T, Bernstein H, Bradley JS, et al. Clinical practice guidelines by the Infectious Diseases Society of America (IDSA): 2018 update: diagnosis, treatment, chemoprophylaxis, and institutional outbreak management of seasonal influenza. Clin Infect Dis. 2018;67: in press.