HealthDay News — For febrile infants age 60 days and younger, urinalysis is highly sensitive and specific for diagnosing urinary tract infections (UTIs), according to a study published online January 16 in Pediatrics.

Leah Tzimenatos, MD, from the University of California, Davis, School of Medicine in Sacramento, and colleagues performed a planned secondary analysis to assess the test characteristics of urinalysis for diagnosing UTIs, with or without associated bacteremia, in febrile infants ≤60 days old. Test characteristics were assessed using two definitions of UTI: growth of ≥50,000 or ≥10,000 colony-forming units (CFUs) per mL of a uropathogen. 

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The researchers found that 289 (7%) of the 4,147 infants analyzed had UTIs with colony counts ≥50,000 CFUs/mL, including 27 (9.3%) with bacteremia. A positive urinalysis for these UTIs exhibited sensitivities of 0.94 (95% confidence interval [CI], 0.91 to 0.97), regardless of bacteremia; 1.00 (95% CI, 0.87 to 1.00) with bacteremia; and 0.94 (95% CI, 0.90 to 0.96) without bacteremia. In all groups, specificity was 0.91 (95% CI, 0.90 to 0.91). The sensitivity and specificity of urinalysis was 0.87 (95% CI, 0.83 to 0.90) and 0.91 (95% CI, 0.90 to 0.92), respectively, for UTIs with colony counts ≥10,000 CFUs/mL.

“The urinalysis is highly sensitive and specific for diagnosing UTIs, especially with ≥50,000 CFUs/mL, in febrile infants ≤60 days old, and particularly for UTIs with associated bacteremia,” the authors write.

One author disclosed financial ties to the pharmaceutical industry.

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