II. Indications

  1. Detection of Influenza A and Influenza B

III. Advantages

  1. Rapid assay for Influenza in the clinic setting
  2. Allows early Neuraminidase Inhibitor start
  3. Indicated for high risk populations (See Influenza)

IV. Disadvantages

  1. Expensive in combination with Neuraminidase Inhibitor
  2. Prevention by Influenza Vaccine is much less expensive

V. Available Tests ($15-20 each)

  1. Flu OIA
    1. Detects both Influenza A and B
    2. Immunoassay for Nucleoprotein
      1. Nasopharyngeal swabs or aspirate
      2. Throat swabs or Sputum
    3. Seven step process performed in 15 minutes
      1. Requires more technician time than with other tests
    4. Efficacy (compared with culture, DFA and PCR)
      1. Test Sensitivity: 62-88% (overall: 80%)
      2. Test Specificity: 52-80% (overall: 73%)
  2. QuickVue Influenza Test
    1. May be used in CLIA-waived labs
    2. Detects both Influenza A and B
    3. Immunoassay for Nucleoprotein
      1. Nasopharyngeal swabs or aspirate
    4. Three step process performed in 10 minutes
    5. Efficacy (compared with viral culture)
      1. Test Sensitivity: 73-81%
      2. Test Specificity: 96-99%
  3. ZstatFlu
    1. May be used in CLIA-waived labs
    2. Detects both Influenza A and B
    3. Enzymatic assay for neuraminidase activity
      1. Throat swab
    4. Four step process performed in 20 minutes
      1. Requires more technician time than with other tests
    5. Efficacy
      1. Lower efficacy than with other tests
        1. Rodriguez (2002) Pediatr Infect Dis 21:193-6 [PubMed]
      2. Test Sensitivity: 51-72%
        1. Influenza A: 65%
        2. Influenza B: 57%
      3. Test Specificity: 93-100%
  4. BD Directigen Flu A+B
    1. Sample from nasopharyngeal aspirate
    2. Only rapid test that distinguishes Influenza A and B
    3. Nine step process performed in 15 minutes
    4. Efficacy
      1. Test Sensitivity: 67-96%
        1. Influenza A: 86%
        2. Influenza B: 81%
      2. Test Specificity: 88-97%
        1. Influenza A: 91%
        2. Influenza B: 99%
  5. BD Directigen Flu A
    1. Detects only Influenza A
    2. Sample from nasopharyngeal aspirate or washing
    3. Eleven step process performed in 15 minutes
    4. Efficacy
      1. Test Sensitivity: 60-77% (Influenza A: 91%)
      2. Test Specificity: 80-90% (Influenza A: 95%)

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