Fig. (3) Urinary nitrate distinguishes patients with acute kidney injury (AKI) from those either at risk or without AKI. Data based on ref. [4], shows median urinary nitrate normalized to urinary creatinine in patients presenting to TCH [N=252]. Bar on left represents combined no AKI and at risk for AKI, whereas the one on the right represents those with AKI. Data are shown as box plots with the heavy line in the box representing the median (50^th percentile) and the ends of the box representing 25^th and 75^th percentiles, respectively. Groups were compared using the non-parametric Mann Whitney U test (*P=0.02). Cr, creatinine. TCH, Texas Children’s Hospital.