title: Validation of a decision rule identifying febrile young girls at high risk for urinary tract infection.
abstract: OBJECTIVE
  To validate a previously published clinical decision rule to predict risk of urinary tract infection in febrile young girls.
  
  
  METHODS
  We performed a retrospective case-control study at a children's hospital emergency department in a different city than that in which the original derivation study took place. Girls younger than 2 years in whom urinalysis and urine culture were performed for evaluation of fever were eligible. Cases consisted of all patients with a positive urine culture result, defined as 50,000 or more colony-forming units per milliliter of a urinary tract pathogen (n = 98). A random sample of patients with a negative urine culture result (n = 114) was also selected as controls. The clinical prediction rule included five risk factors: age younger than 12 months, white race, temperature of 39.0 degrees C or higher, absence of any other potential source of fever, and fever for 2 days or more. The sensitivity and false-positive rate of this rule were calculated at different cutoff values.
  
  
  RESULTS
  The overall discriminative ability of the rule, as indicated by the area under the receiver-operator characteristic curve (AUC), was similar in this validation sample (AUC = 0.72) to that in the original study (AUC = 0.76). However, in the validation sample, the presence of three or more risk factors (rather than two or more as in the original study) appeared to be the optimum cutoff to define a positive rule, which results in an indication for obtaining further diagnostic testing (sensitivity, 88% [95% CI, 79-94%]; false-positive rate, 70% [95% CI, 61-79%]).
  
  
  CONCLUSIONS
  A simple clinical decision rule previously developed to predict urinary tract infection based on five risk factors performs similarly in a different patient population.
authors.affiliation: Section of Emergency Medicine, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin, USA. mgorelic@mcw.edu
authors.forename: Marc H
authors.initials: MH
authors.lastname: Gorelick
authors.forename: Alejandro
authors.initials: A
authors.lastname: Hoberman
authors.forename: Diana
authors.initials: D
authors.lastname: Kearney
authors.forename: Ellen
authors.initials: E
authors.lastname: Wald
authors.forename: Kathy N
authors.initials: KN
authors.lastname: Shaw
mesh_terms: D019540:Area Under Curve; D001437:Bacteriuria / Q000175:diagnosis / Q000382:microbiology; D016022:Case-Control Studies; D002675:Child, Preschool; D015169:Colony Count, Microbial; D003661:Decision Support Techniques; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005189:False Positive Reactions; D005260:Female; D005334:Fever / Q000209:etiology*; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D010414:Pennsylvania / Q000453:epidemiology; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014552:Urinary Tract Infections / Q000175:diagnosis* / Q000453:epidemiology; D044465:White People