title: Evaluation of QuickVue influenza A+B rapid test for detection of pandemic influenza A/H1N1 2009.
abstract: BACKGROUND
  A novel influenza A/H1N1 emerged in early 2009 and by June 2009 was declared a pandemic by WHO. Rapid influenza antigen detection tests have been used to diagnose seasonal influenza but have not been adequately evaluated for the pandemic strain among all age groups. In the Philippines, pandemic influenza A/H1N1 2009 was first detected in May 2009 and by July 2009, 3207 cases and 6 deaths were reported.
  
  
  OBJECTIVE
  Using RT-PCR as the gold standard, clinical sensitivity/specificity of Quidel QuickVue (QV) influenza A+B was estimated across all age groups for pandemic influenza A/H1N1 using nasal swabs in a hospital setting. Effect of age, viral titers (Ct values), and timing of collection on QV sensitivity to detect pandemic influenza A/H1N1 2009 was also determined.
  
  
  METHODS
  Febrile patients with influenza-like illness (n=360) at the V. Luna General Hospital, Manila from 1 June to 31 August 2009 were included. Nasal swabs were tested using QV and RT-PCR.
  
  
  RESULTS
  Of 360 nasal specimens 226 (63%) were positive for pandemic influenza A/H1N1. QV sensitivity was 63% (95% confidence interval (CI): 56-69%), specificity was 96% (95% CI: 91-99%), positive predictive value was 97% (CI: 93-99%), and negative predictive value was 57% (95% CI: 49-64%). Patient's age, fever severity, presenting symptoms or number of symptoms did not significantly affect QV sensitivity, however QV sensitivity was correlated with decreasing Ct values.
  
  
  CONCLUSIONS
  QuickVue demonstrated moderate sensitivity for pandemic influenza A/H1N1 infection. There was a significant inverse association between Ct values and QV sensitivity for pandemic influenza A/H1N1.
authors.affiliation: Department of Virology, Armed Forces Research Institute of Medical Sciences, 315/6 Rajvithi Road, Bangkok, 10400 Thailand. VelascoJM@afrims.org
authors.forename: John Mark S
authors.initials: JM
authors.lastname: Velasco
authors.forename: Maribel L
authors.initials: ML
authors.lastname: Montesa-Develos
authors.forename: Richard G
authors.initials: RG
authors.lastname: Jarman
authors.forename: Ma Nila B
authors.initials: MN
authors.lastname: Lopez
authors.forename: Robert V
authors.initials: RV
authors.lastname: Gibbons
authors.forename: Maria Theresa G
authors.initials: MT
authors.lastname: Valderama
authors.forename: In-Kyu
authors.initials: IK
authors.lastname: Yoon
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000956:Antigens, Viral / Q000302:isolation & purification*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007223:Infant; D053118:Influenza A Virus, H1N1 Subtype / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000821:virology; D010679:Philippines; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D014773:Virology / Q000379:methods*; D055815:Young Adult
chemical_list: D000956:Antigens, Viral; D011933:Reagent Kits, Diagnostic