Kidney Injury refers to a disease in which the kidney is damaged to different degrees leading to abnormal kidney function or function loss, which can be divided into Acute Kidney Injury and Chronic Kidney Injury according to clinical manifestations. Acute Kidney Injury (AKI) is a sudden decline in kidney function, resulting in the retention of urea and other nitrogenous wastes, as well as dysregulation of extracellular fluid volume and electrolytes, and may be accompanied by oliguria (<400ml/24h or 17ml/h) or anuria (<100ml/24h). Normally the symptoms are hidden in the early stage, and tend to occur in the elderly, people with diabetes, hypertension, kidney disease, etc. The incidence of AKI is 3%~10% in general hospitals, 30%~60% in intensive care units, and the mortality rate of critical AKI is as high as 30%~80%.

Neutrophil gelatinase-associated lipid carrier protein (NGAL) and urinary microalbumin (MALB) are common and highly specific biomarkers that can reflect kidney injury.