title: Optical immunoassay for rapid detection of group A beta-hemolytic streptococci. Should culture be replaced?
abstract: OBJECTIVE
  To evaluate an optical immunoassay rapid antigen test to detect group A beta-hemolytic streptococci directly from throat swab specimens.
  
  
  METHODS
  Criterion standard with "blinded" comparison. Double-swab pharyngeal samples were obtained; one swab was cultured and the other was used for the rapid antigen test.
  
  
  METHODS
  Microbiology laboratory in a primary care center at a university teaching hospital.
  
  
  METHODS
  Two hundred sixty-two outpatients with pharyngitis.
  
  
  METHODS
  The results of the optical immunoassay rapid antigen test were compared with results of standard aerobic culture.
  
  
  RESULTS
  Sixty-two (24%) of 262 samples were culture-positive; 48 of these 62 were positive by the optical immunoassay rapid test (sensitivity, 77%). Of the 200 culture-negative samples, seven (4%) were positive by the rapid test (specificity, 96%).
  
  
  CONCLUSIONS
  The optical immunoassay performed well, but like other rapid tests, is not sensitive enough to replace standard culture for detection of group A beta-hemolytic streptococci.
authors.affiliation: Department of Pediatrics, University of Virginia Medical Center, Charlottesville, USA.
authors.forename: T A
authors.initials: TA
authors.lastname: Schlager
authors.forename: G A
authors.initials: GA
authors.lastname: Hayden
authors.forename: W A
authors.initials: WA
authors.lastname: Woods
authors.forename: S M
authors.initials: SM
authors.lastname: Dudley
authors.forename: J O
authors.initials: JO
authors.lastname: Hendley
mesh_terms: D000293:Adolescent; D000942:Antigens, Bacterial / Q000276:immunology*; D001431:Bacteriological Techniques; D016009:Chi-Square Distribution; D002648:Child; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D008297:Male; D010612:Pharyngitis / Q000175:diagnosis / Q000276:immunology* / Q000382:microbiology; D010614:Pharynx / Q000276:immunology / Q000382:microbiology; D013290:Streptococcal Infections / Q000175:diagnosis / Q000276:immunology* / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D000942:Antigens, Bacterial