CRP and bacterial urinary tract infection: The median (IQR) urinary levels of CRP (ng/mL)/creatinine (mg/dL) were significantly higher in children with UTI [n = 32, 3.2 (13.6)] compared to children without bacterial infection [n = 22, 0.2 (0.5), p < 0.001], also across both age groups, infants < 3 months [n = 11, 5.8 (22.0) vs. n = 6, 0.4 (0.4); p = 0.002], and children aged 3 months or older [n = 21, 1.9 (13.8) vs. n = 16, 0.1 (0.7); p = 0.001; Figure 2 and Supplementary Figure 2].