Validation and modification of streptococcal pharyngitis clinical prediction rules

Mayo Clin Proc. 2003 Mar;78(3):289-93. doi: 10.4065/78.3.289.


Objective: To validate a simplified version of the Walsh clinical prediction rules (CPRs) for the presence of streptococcal pharyngitis in an inner-city, ethnically diverse population.

Patients and methods: This prospective study conducted in New York City, NY, from January 1,1997, to May 31,1997, consisted of 171 consecutive adult walk-in patients who presented with symptoms of upper respiratory tract infection and/or sore throat. The patients were assessed by using 5 clinical factors: cough, exposure to known streptococcal contact, temperature, tonsillar-pharyngeal exudates, and cervical lymphadenopathy. Throat cultures for group A beta-hemolytic streptococcus were obtained from all patients. Clinicians assessing the patients were unaware of throat culture results, and those processing the throat cultures were blinded to the clinical predictors.

Results: The prevalence of streptococcal pharyngitis was 24% (95% confidence interval, 18%-30%). The simplified version of the Walsh CPR for streptococcal pharyngitis predicted accurately the probability of a positive culture in our diverse population (area under the receiver operating characteristic curve, 0.71). The simplified CPR also showed clinically useful likelihood ratios and posterior probabilities.

Conclusion: A simplified version of the Walsh CPR is accurate for diagnosing streptococcal pharyngitis in an inner-city population. This finding should provide clinicians more confidence in applying the CPR in similar clinical settings.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Confidence Intervals
  • Female
  • Humans
  • Male
  • Middle Aged
  • New York City / epidemiology
  • Pharyngitis / diagnosis*
  • Pharyngitis / epidemiology
  • Prevalence
  • Prospective Studies
  • ROC Curve
  • Sensitivity and Specificity
  • Streptococcal Infections / diagnosis*
  • Streptococcal Infections / epidemiology
  • Streptococcus pyogenes / isolation & purification*
  • Urban Population