In Alge et al.'s study, urinary angiotensinogen could be useful as a prognostic acute kidney injury biomarker in the setting of the intensive care unit; in a recent study that used a definition of prerenal azotemia, which was very similar to Alge et al.'s, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), IL-18, and kidney injury molecule 1 (KIM)-1 were elevated in ICU patients with prerenal AKI compared to those without AKI but were lower than values for patients whose AKI did not resolve within 48 hrs [18]. This evidence concerns the gene IL18 and acute kidney injury.