LCN2 and acute kidney injury: At present, there are some new biomarkers, such as cystatin C (CysC), neutrophil gelatinase-associated lipocalin (NGAL), and kidney injury molecule 1 (KIM-1), which are the most sensitive indicators for early diagnosis of acute renal failure and have higher specificity for ischemic or nephrotoxic kidney disease, but most of them have not been widely used in clinical practice.