DKK3 and acute kidney injury: It is produced by tubular cells and neutrophils to diagnose the severity of AKI.[12,13] L-FABP, a 14 kDa intracellular lipid chaperone produced by proximal tubule help diagnose AKI.[14] KIM-1, a type of transmembrane glycoprotein released into urine, which predicted and identify the severity of AKI.[15] Dickkopf-3 is secreted into urine under intensive stress of AKI, which help assess the risk of AKI.[16] Cystatin C, 13 kDa cysteine protease inhibitor produced by nucleated human cells, is filtered into plasma and regarded as the biomarkers of diagnose and severity of AKI.[17]