BACKGROUND: There is no consensus favoring a particular strategy for evaluating patients with pharyngitis.
OBJECTIVE: To compare a clinical decision aid and a rapid office-based point of care (POC) test with routine culture for group A β-hemolytic
streptococcus (GAS).
DESIGN: Prospective observational study.
PARTICIPANTS: Among 179 patients enrolled, 150 were eligible and 148 had POC testing and cultures initially performed.
MEASUREMENTS: An encounter form included eligibility criteria, clinical information based upon the Centor rule, and treatment provided.
Sensitivity and specificity of POC test compared to routine culture for GAS.
RESULTS: Thirty-eight patients (25.7%) had a positive GAS culture. The POC test was 92.1% sensitive (95% confidence interval [CI]
80% to 98%) and 100% specific (95% CI 97% to 100%). Although the Centor rule did not adequately discriminate among symptomatic
patients with or without GAS (receiver operating curve area 0.63), the 3 patients with a false-negative POC test had a Centor
score of less than 2. Among patients with a negative POC test, 26% initially received antibiotics.
CONCLUSIONS: For patients with a Centor score of ≥2, a POC test was highly sensitive for GAS. Future studies should confirm these results
and assess whether implementation of POC testing as part of a local practice guideline can decrease variability in testing
and treatment.
Key words pharyngitis - point of care testing - diagnostic accuracy - guideline
Dr. Atlas has performed consulting for Aventis-Sanofi Pharmaceuticals for unrelated work.
This work was presented in part at a New England Regional meeting of the Society of General Internal Medicine, Boston, Mass,
on March 5, 2004.
This work was supported by institutional funding through the Massachusetts General Hospital Primary Care Operations Improvement
program.