Fig. 2

Urinary concentrations of kynurenic acid and kynurenic acid/tryptophan ratio in AKI patients with/without early recovery. Results are given on a linear scale and displayed as boxplot summaries. The middle line in the box represents the mean, and the whiskers represent the standard error of the mean. Urinary concentrations of creatinine normalized kynurenic acid (KynA) were increased in patients with late−/non-recovery (LNR) when compared to patients with early recovery (ER) (*p ≤ 0.005, **p < 0.001 and ***p < 0.0001). The urinary ratio of KynA/tryptophan was higher in LNR patients compared to ER patients. (*p = 0.01, *** < 0.0001). Corresponding serum creatinine concentrations in mg/dl are given below the graph