Predictive value of dipstick urinalysis for detecting pyelonephritis in children aged 0-12 months

Urinary tract infections (UTIs) are the most common serious bacterial infections during the first year of life. Symptoms of UTI in young children are non-specific, making diagnosis challenging.

We conducted a retrospective single-center study over a period of 5 years. Urine samples collected by suprapubic aspiration, clean catch, or bladder catheterization in children aged 0-12 months presenting to the emergency department with fever without focus and suspected UTI during this period were reviewed from the laboratory archives. We divided our population into two groups of 0-3 and 4-12 months. Data on dipstick urinalysis were collected, with urine culture as the reference standard. Statistical analysis-including sensitivity, specificity, diagnostic odds ratio, likelihood ratio, positive predictive value (PPV), and negative predictive value-was performed for the following dipstick urinalysis parameters: leucocyte esterase alone, nitrites alone, leucocyte esterase and nitrites, leucocyte esterase and/or nitrites.

Statistical analysis showed that in the 0-3-month group, specificity was 94% for leucocyte esterase (LE) and 99% for nitrites (Nit). Sensitivity was 60% for LE and 25% for nitrites. PPV was 87% for LE and 96% for nitrites. In the 4-12-month group, specificity was 91% for LE and 98% for nitrites. Sensitivity was 71% for LE and 25% for nitrites. PPV was 82% for LE and 87% for nitrites. Combined analysis of leucocyte esterase and/or nitrites and leucocyte esterase and nitrites showed no improvement in performance.

Dipstick analysis is a reliable bedside test for ruling in UTI in children under 12 months, particularly in the presence of positive nitrites for children less than 3 months of age. Urine culture remains necessary for diagnostic confirmation.

This study adds to the diagnostic performance of dipstick urinalysis in infants and neonates, with a specificity of 92%-99% and positive predictive value of 82%-96%.