title: Performance of five FDA-approved rapid antigen tests in the detection of 2009 H1N1 influenza A virus.
abstract: Rapid antigen tests are commonly used by clinicians for rapid, simple, point-of-care testing. Five rapid antigen tests were shown to have low sensitivity (40.3-58.8%) when compared to real-time RT-PCR using nasal wash specimens from patients with influenza-like-illness (N = 167) that were collected previously and confirmed as 2009 pandemic influenza A (H1N1)-positive by PCR. Rapid antigen test sensitivity correlated with virus levels in nasal secretions when comparisons were made to cycle threshold (C(T)) values obtained from real-time RT-PCR. When C(T) values are <25 (equating to viral concentrations of >10(4)  TCID(50)/ml) sensitivity for all five rapid antigen kits was high (range: 83-94% positive); however, when C(T) values are >30 (10(2)  TCID(50)/ml), sensitivities of only 16-18% were observed for four of five rapid antigen kits. The Directigen EZ Flu A + B test detected more positive samples (35%) at lower viral concentrations with C(T) values >30 when compared with other commercial kits (P = 0.05). Rapid antigen test results must be interpreted with caution, and negative specimens may need confirmation by sensitive molecular assays.
authors.affiliation: Department of Pediatrics, San Antonio Military Medical Center, Ft Sam, Houston, Texas 78234, USA. deena.sutter@amedd.army.mil
authors.forename: Deena E
authors.initials: DE
authors.lastname: Sutter
authors.forename: Sue A
authors.initials: SA
authors.lastname: Worthy
authors.forename: Donna M
authors.initials: DM
authors.lastname: Hensley
authors.forename: Ashley M
authors.initials: AM
authors.lastname: Maranich
authors.forename: Donna M
authors.initials: DM
authors.lastname: Dolan
authors.forename: Gerald W
authors.initials: GW
authors.lastname: Fischer
authors.forename: Luke T
authors.initials: LT
authors.lastname: Daum
mesh_terms: D000956:Antigens, Viral / Q000032:analysis*; D012634:Bodily Secretions / Q000821:virology; D019411:Clinical Laboratory Techniques / Q000379:methods*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis* / Q000821:virology*; D009666:Nose / Q000821:virology; D019095:Point-of-Care Systems; D012680:Sensitivity and Specificity; D019562:Viral Load
chemical_list: D000956:Antigens, Viral