title: Association between C-reactive protein rapid test and group A streptococcus infection in acute pharyngitis.
abstract: BACKGROUND
  The diagnosis of streptococcal infection is usually made with the use of Centor criteria, but some family doctors also rely on the determination of C-reactive protein (CRP) to guide antibiotic therapy.
  
  
  METHODS
  This was an observational study conducted in a health center. Adults with acute pharyngitis and the presence of the 4 Centor criteria (tonsillar exudates, tender cervical glands, history of fever, and absence of cough) were recruited. The patients underwent a pharyngotonsillar swab for microbiologic study and a CRP rapid test during the consultation.
  
  
  RESULTS
  A total of 149 patients were enrolled. The most frequent etiology was group A streptococcus, present in 83 cases (55.7%). The highest CRP concentration was observed among patients with group C streptococcus infection, with a mean of 56.3 mg/L (95% confidence interval, 25.7-86.5 mg/L). For patients with group A streptococcus infection, the mean CRP value was 34.4 (95% confidence interval, 25.6-43.3 mg/L).
  
  
  CONCLUSIONS
  CRP concentrations are not associated with group A streptococcus infection in patients with acute pharyngitis. The use of this point of care test is therefore not useful for distinguishing patients who require antibiotic therapy.
authors.affiliation: the Institute of Primary Care and Public Health, Cardiff University School of Medicine, Cardiff, UK; Primary Care Center Jaume I, Tarragona, Spain; and the Department of Laboratory and Microbiology, Hospital Joan XXIII, Tarragona, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Calviño
authors.forename: Carl
authors.initials: C
authors.lastname: Llor
authors.forename: Frederic
authors.initials: F
authors.lastname: Gómez
authors.forename: Eva
authors.initials: E
authors.lastname: González
authors.forename: Carolina
authors.initials: C
authors.lastname: Sarvisé
authors.forename: Silvia
authors.initials: S
authors.lastname: Hernández
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010612:Pharyngitis / Q000097:blood / Q000382:microbiology*; D019095:Point-of-Care Systems; D013290:Streptococcal Infections / Q000097:blood*; D013297:Streptococcus pyogenes / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002097:C-Reactive Protein
keywords: Antibiotics; C-Reactive Protein; Infectious Diseases; Pharyngitis; Streptococcus Group A