LCN2 and acute kidney injury: Several scoring systems can predict the mortality rate of critically ill patients in ICU, such as Assessment and Chronic Health Evaluation II (APACHE II) and the Sequential Organ Failure Assessment (SOFA) scoring systems; in addition, biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and c-terminal fibroblast growth factor 23 (cFGF-23) can also predict the outcome of patients in ICU with AKI [10,11,12].