title: The rational clinical examination. Does this patient have strep throat?
abstract: BACKGROUND
  Sore throat is a common complaint, and identifying patients with group A beta-hemolytic streptococcal pharyngitis (strep throat) is an important task for clinicians. Previous reviews have not systematically reviewed and synthesized the evidence.
  
  
  OBJECTIVE
  To review the precision and accuracy of the clinical examination in diagnosing strep throat.
  
  
  METHODS
  MEDLINE search for articles about diagnosis of strep throat using history-taking and physical examination.
  
  
  METHODS
  Large blinded, prospective studies (having > or =300 patients with sore throat) reporting history and physical examination data and using throat culture as the reference standard were included. Of 917 articles identified by the search, 9 met all inclusion criteria.
  
  
  METHODS
  Pairs of authors independently reviewed each article and used consensus to resolve discrepancies.
  
  
  RESULTS
  The most useful findings for evaluating the likelihood of strep throat are presence of tonsillar exudate, pharyngeal exudate, or exposure to strep throat infection in the previous 2 weeks (positive likelihood ratios, 3.4, 2.1, and 1.9, respectively) and the absence of tender anterior cervical nodes, tonsillar enlargement, or exudate (negative likelihood ratios, 0.60, 0.63, and 0.74, respectively). No individual element of history-taking or physical examination is accurate enough by itself to rule in or rule out strep throat. Three validated clinical prediction rules are described for adult and pediatric populations.
  
  
  CONCLUSIONS
  While no single element of history-taking or physical examination is sufficiently accurate to exclude or diagnose strep throat, a well-validated clinical prediction rule can be useful and can help physicians make more informed use of rapid antigen tests and throat cultures.
authors.affiliation: Department of Family Practice, Michigan State University, East Lansing 48824-1315, USA. mark.ebell@ht.msu.edu
authors.forename: M H
authors.initials: MH
authors.lastname: Ebell
authors.forename: M A
authors.initials: MA
authors.lastname: Smith
authors.forename: H C
authors.initials: HC
authors.lastname: Barry
authors.forename: K
authors.initials: K
authors.lastname: Ives
authors.forename: M
authors.initials: M
authors.lastname: Carey
mesh_terms: D000328:Adult; D000465:Algorithms; D002648:Child; D003657:Decision Making; D003937:Diagnosis, Differential; D006801:Humans; D008487:Medical History Taking; D010612:Pharyngitis / Q000175:diagnosis / Q000382:microbiology*; D010808:Physical Examination; D011336:Probability; D013290:Streptococcal Infections / Q000175:diagnosis* / Q000503:physiopathology; D013297:Streptococcus pyogenes / Q000302:isolation & purification