Efficiency of a clinical prediction model for selective rapid testing in children with pharyngitis: A prospective, multicenter study

PLoS One. 2017 Feb 24;12(2):e0172871. doi: 10.1371/journal.pone.0172871. eCollection 2017.


Background: There is controversy whether physicians can rely on signs and symptoms to select children with pharyngitis who should undergo a rapid antigen detection test (RADT) for group A streptococcus (GAS). Our objective was to evaluate the efficiency of signs and symptoms in selectively testing children with pharyngitis.

Materials and methods: In this multicenter, prospective, cross-sectional study, French primary care physicians collected clinical data and double throat swabs from 676 consecutive children with pharyngitis; the first swab was used for the RADT and the second was used for a throat culture (reference standard). We developed a logistic regression model combining signs and symptoms with GAS as the outcome. We then derived a model-based selective testing strategy, assuming that children with low and high calculated probability of GAS (<0.12 and >0.85) would be managed without the RADT. Main outcomes and measures were performance of the model (c-index and calibration) and efficiency of the model-based strategy (proportion of participants in whom RADT could be avoided).

Results: Throat culture was positive for GAS in 280 participants (41.4%). Out of 17 candidate signs and symptoms, eight were retained in the prediction model. The model had an optimism-corrected c-index of 0.73; calibration of the model was good. With the model-based strategy, RADT could be avoided in 6.6% of participants (95% confidence interval 4.7% to 8.5%), as compared to a RADT-for-all strategy.

Conclusions: This study demonstrated that relying on signs and symptoms for selectively testing children with pharyngitis is not efficient. We recommend using a RADT in all children with pharyngitis.

Publication types

  • Multicenter Study

MeSH terms

  • Calibration
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Decision Support Systems, Clinical
  • Female
  • France
  • Humans
  • Male
  • Pharyngitis / diagnosis*
  • Pharynx / microbiology
  • Predictive Value of Tests
  • Prospective Studies
  • Regression Analysis
  • Streptococcal Infections / diagnosis*
  • Streptococcus pyogenes*

Grants and funding

This work was supported by a research grant from the French Ministry of Health (PHRC Régional 2012, AOR 12089). The clinical study was internally funded by ACTIV and externally by Dectrapharm, manufacturer of the rapid test. JFC was supported by educational grants from Agence Régionale de Santé d’Ile-de-France, Laboratoires Guigoz - Société Française de Pédiatrie - Groupe de Pédiatrie Générale - Groupe de Recherches Epidémiologiques en Pédiatrie, and a research grant from Assistance Publique Hôpitaux de Paris (Année Médaille de l’Internat 2013). The Funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.