title: External Validation of the STONE Score, a Clinical Prediction Rule for Ureteral Stone: An Observational Multi-institutional Study.
abstract: OBJECTIVE
  The STONE score is a clinical decision rule that classifies patients with suspected nephrolithiasis into low-, moderate-, and high-score groups, with corresponding probabilities of ureteral stone. We evaluate the STONE score in a multi-institutional cohort compared with physician gestalt and hypothesize that it has a sufficiently high specificity to allow clinicians to defer computed tomography (CT) scan in patients with suspected nephrolithiasis.
  
  
  METHODS
  We assessed the STONE score with data from a randomized trial for participants with suspected nephrolithiasis who enrolled at 9 emergency departments between October 2011 and February 2013. In accordance with STONE predictors, we categorized participants into low-, moderate-, or high-score groups. We determined the performance of the STONE score and physician gestalt for ureteral stone.
  
  
  RESULTS
  Eight hundred forty-five participants were included for analysis; 331 (39%) had a ureteral stone. The global performance of the STONE score was superior to physician gestalt (area under the receiver operating characteristic curve=0.78 [95% confidence interval {CI} 0.74 to 0.81] versus 0.68 [95% CI 0.64 to 0.71]). The prevalence of ureteral stone on CT scan ranged from 14% (95% CI 9% to 19%) to 73% (95% CI 67% to 78%) in the low-, moderate-, and high-score groups. The sensitivity and specificity of a high score were 53% (95% CI 48% to 59%) and 87% (95% CI 84% to 90%), respectively.
  
  
  CONCLUSIONS
  The STONE score can successfully aggregate patients into low-, medium-, and high-risk groups and predicts ureteral stone with a higher specificity than physician gestalt. However, in its present form, the STONE score lacks sufficient accuracy to allow clinicians to defer CT scan for suspected ureteral stone.
authors.affiliation: Department of Emergency Medicine, University of California, San Francisco, San Francisco, CA. Electronic address: ralph.wang@ucsf.edu.
authors.forename: Ralph C
authors.initials: RC
authors.lastname: Wang
authors.affiliation: Department of Emergency Medicine, University of California, San Francisco, San Francisco, CA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Rodriguez
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Moghadassi
authors.affiliation: Department of Emergency Medicine, Massachusetts General Hospital, Boston, MA.
authors.forename: Vicki
authors.initials: V
authors.lastname: Noble
authors.affiliation: Department of Emergency Medicine, John H. Stroger Jr. Hospital of Cook County, Chicago, IL.
authors.forename: John
authors.initials: J
authors.lastname: Bailitz
authors.affiliation: Division of Emergency Medicine, University of Utah, Salt Lake City, UT.
authors.forename: Mike
authors.initials: M
authors.lastname: Mallin
authors.affiliation: Department of Emergency Medicine, Jacobi Medical Center, Albert Einstein College of Medicine, New York, NY.
authors.forename: Jill
authors.initials: J
authors.lastname: Corbo
authors.affiliation: Department of Emergency Medicine, Los Angeles County at the University of Southern California, Los Angeles, CA.
authors.forename: Tarina L
authors.initials: TL
authors.lastname: Kang
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA.
authors.forename: Phillip
authors.initials: P
authors.lastname: Chu
authors.affiliation: Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA.
authors.forename: Steve
authors.initials: S
authors.lastname: Shiboski
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA; Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Smith-Bindman
mesh_terms: D000328:Adult; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography; D014481:United States; D014514:Ureteral Calculi / Q000000981:diagnostic imaging*