title: [Validation of a rapid antigenic test in the diagnosis of pharyngitis caused by group a beta-haemolytic Streptococcus].
abstract: OBJECTIVE
  To determine the validity of the rapid antigen test (RAT) OSOM StrepA Genzyme for the diagnosis of acute pharyngitis caused by group A beta-haemolytic strep (GABHS).
  
  
  METHODS
  Diagnostic techniques survey.
  
  
  METHODS
  Urban primary care centre, Spain.
  
  
  METHODS
  All patients over 14 years old seen in 6 surgeries with sore throat and 2 or more Centor criteria: pharyngotonsillar exudate, tender laterocervical nodes, absence of coughing, and/or history or presence of fever.
  
  
  METHODS
  Pharyngeal swabs were taken from all the patients, one for RAT and another to send for culture in the microbiology department.
  
  
  RESULTS
  A total of 182 patients were evaluable, with a mean age of 30.6 (12.1) years of which 116 were women (63.7%); 63 patients had 2 Centor criteria; 83 had 3 and 36, the 4 criteria. The culture was positive in 102 patients (56%), with GABHS showing infection in forty (22%; 95% confidence interval [CI], 21.2-22.8). Group C Streptococcus was isolated in 26 patients (14.3%). GABHS was higher among patients with four Centor criteria (38.9% vs 25.3% observed among those with 3 criteria and 7.9% with 2 criteria; P<.001). Sensitivity of RAT was 95%, with a specificity of 93%, a positive predictive value of 79.2% and a negative predictive value of 98.5%.
  
  
  CONCLUSIONS
  These results show the usefulness of RAT for diagnosing streptococcal pharyngitis. Its use should be spread to all primary care practices.
authors.affiliation: Medicina de Familia, Centro de Salud Jaume I, Tarragona, Spain. carles.llor@urv.cat
authors.forename: Carles
authors.initials: C
authors.lastname: Llor
authors.forename: Silvia
authors.initials: S
authors.lastname: Hernández Anadón
authors.forename: Frederic Francesc
authors.initials: FF
authors.lastname: Gómez Bertomeu
authors.forename: Josep Maria
authors.initials: JM
authors.lastname: Santamaria Puig
authors.forename: Olga
authors.initials: O
authors.lastname: Calviño Domínguez
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Fernández Pagés
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007159:Immunologic Tests; D008297:Male; D010612:Pharyngitis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology*; D011446:Prospective Studies; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000276:immunology; D013297:Streptococcus pyogenes; D013997:Time Factors