Comparison of the NOW Influenza A & B, NOW Flu A, NOW Flu B, and Directigen Flu A+B assays, and immunofluorescence with viral culture for the detection of influenza A and B viruses

Diagn Microbiol Infect Dis. 2007 Jan;57(1):67-70. doi: 10.1016/j.diagmicrobio.2006.11.003.


To evaluate the Binax NOW Influenza A & B combination assay, we tested upper respiratory tract samples in parallel with the Binax NOW Flu A and Binax NOW Flu B assays, the Becton-Dickinson Directigen Flu A+B assay, and immunofluorescence, and the results were compared with viral culture. Of the 521 samples tested, influenza A was cultured from 113 and influenza B from 6. There were no significant differences in the performance of all rapid antigen tests, with sensitivities of 53% to 59% for detecting influenza A compared with culture and immunofluorescence (80%). The sensitivities for all rapid tests were significantly higher for nasopharyngeal samples than for throat swabs. The Binax NOW Influenza A & B assay performed as well as other rapid assays. Commercial antigen detection assays are useful tools for the rapid diagnosis of influenza; however, confirmatory testing is always recommended. The use of nasopharyngeal samples for all rapid detection methods should be strongly encouraged.

Publication types

  • Comparative Study
  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antigens, Viral / analysis*
  • Child
  • Child, Preschool
  • Female
  • Fluorescent Antibody Technique
  • Humans
  • Infant
  • Infant, Newborn
  • Influenza A virus / isolation & purification*
  • Influenza B virus / isolation & purification*
  • Influenza, Human / diagnosis*
  • Influenza, Human / virology
  • Male
  • Middle Aged
  • Nasopharynx / virology
  • Pharynx / virology
  • Predictive Value of Tests
  • Reagent Kits, Diagnostic*
  • Sensitivity and Specificity
  • Time Factors
  • Virus Cultivation


  • Antigens, Viral
  • Reagent Kits, Diagnostic