To develop a clinical prediction rule to identify febrile young girls needing urine culture for evaluation of urinary tract infection (UTI).
Prospective cohort study.
Urban children's hospital emergency department.
All girls younger than 2 years (N=1469) presenting to the emergency department with fever (temperature ≥38.3°C) and without an unequivocal source of fever during a 12-month period.
Main Outcome Measures
The outcome of interest was UTI, defined as a catheterized urine culture with pure growth of 104 colonies/mL or greater. Candidate predictors included demographic, historical, and physical examination variables. Clinical prediction rules were developed using multiple logistic regression after screening variables for univariate association and reliability.
The presence of 2 or more of the following 5 variables—less than 12 months old, white race, temperature of 39.0°C or higher, fever for 2 days or more, and absence of another source of fever on examination—predicted UTI with a sensitivity of 0.95 (95% confidence interval, 0.85-0.99) and a specificity of 0.31 (95% confidence interval, 0.28-0.34). In the study population, with an overall prevalence of UTI of 4.3%, the positive predictive value of a score of 2 or more was 6.4% and the negative predictive value of a score of less than 2 was 0.8%.
Using this clinical decision rule, a strategy of obtaining urine cultures from girls younger than 2 years with a score of 2 or more would lead to identification of 95% of children with UTI and elimination of 30% of unnecessary urine cultures.