Pediatrics

Does lowering the positive cutoff of urine culture optimize pediatric UTI diagnosis?

October 3, 2023

In this cohort of young, febrile children undergoing bladder catheterization to rule out urinary tract infection (UTI), researchers calculated the accuracy of conventional culture at different cutoffs to identify the one that provides the optimal balance of sensitivity and specificity.

• The study included 341 children 1 month to 3 years of age (74% girls; 40% ages 2 to 11 months; 67% White) who underwent bladder catheterization. Among these children, there were 46 confirmed UTIs.
• Using 16S rRNA gene amplicon sequencing as the reference standard, study authors calculated the accuracy of urine culture at various cutoffs (10,000; 50,000; and 100,000 colony forming units per mL).
• When using a cutoff of 10,000 CFU/mL, the sensitivity and specificity of urine culture were 98% (95% confidence interval [CI]: 93%-100%) and 99% (95% CI: 97%-100%), respectively.
• Using a cutoff of 50,000 colony forming units per mL decreased sensitivity to 80% (95% CI: 68%-93%) without changing the specificity, and a cutoff of 100,000 further decreased sensitivity to 70% (95% CI: 55%-84%).

Source:

Shaikh N. (2023, Oct 1). Pediatrics. Support for the Use of a New Cutoff to Define a Positive Urine Culture in Young Children. https://pubmed.ncbi.nlm.nih.gov/37691613/