D-dimer Versus Procalcitonin for the Diagnosis of Pediatric UTI and Prediction of Renal Parenchymal Involvement

Previous studies have investigated the applicability of different serum biomarkers for the diagnosis of urinary tract infection (UTI) and differentiation between acute pyelonephritis (APN) and cystitis. We aimed to compare serum D-dimer with procalcitonin (PCT) for the diagnosis of UTI and prediction of APN in a pediatric population.

This cross-sectional study included children aged 1 month to 14 years with their first UTI episode confirmed by positive urine culture. Serum PCT and D-dimer were measured in all participants before the initiation of antibiotic therapy. Dimercaptosuccinic acid (DMSA) scan was performed in all children within 2 months of UTI resolution to determine renal parenchymal involvement.

From the 43 children included in this study, 69.8% were female. D-dimer level was significantly higher in boys (823.26 ± 298.19 vs. 582.96 ± 359.96 ng/mL; P < .05). PCT level was comparable in boys and girls (P > .05). Logistic regression revealed that regardless of gender, children aged 2 to 6 years had significantly higher chance of at least one positive marker compared to those 6 to 14 years (OR = 6.12, 95% CI: 1.09 to 34.47, P < .05). The area under the curve value from the receiver operating characteristic curve of D-dimer ≥ 513 ng/mL for prediction of APN was 0.873, with a sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of 84.8, 90, 96.6, 64.3, and 86%; respectively.

According to the results of the current study, 81.4% of children aged 1 month to 14 years with their first UTI episode, were either PCT or D-dimer positive. D-dimer appears to have the highest diagnostic performance for the detection of APN.