Established markers of kidney function, such as creatinine, have considerable limitations in the diagnosis of delayed graft function (DGF) after kidney transplantation (KT). Indeed, creatinine does not accurately reflect minor changes of renal function as its levels change only upon significant fluctuations of the latter. CAF22 is a molecule which arises from the degradation of a larger protein and it is proposed to be a reliable and more sensitive marker of renal function. This study aims to further clarify this issue by measuring blood and urine concentrations of CAF22 and comparing them with creatinine levels before and after KT.