Endogenous creatinine clearance, in fact, is an indicator of renal function. In clinical terms, endogenous creatinine clearance can be equated to approximately the glomerular filtration rate. The professional definition of endogenous creatinine clearance is actually the removal of endogenous creatinine from a number of milliliters of plasma per unit time, which is called endogenous creatinine clearance. Endogenous creatinine clearance can reflect kidney damage earlier than blood creatinine, because when endogenous creatinine clearance drops to 50 ml/min, blood creatinine will appear to be elevated and be so recognized. The clinical significance of endogenous creatinine clearance is, firstly, to determine the damage of kidney function. Secondly, many clinical medications are classified by endogenous creatinine clearance, for example, for endogenous creatinine clearance less than 30ml/min, thiazide diuretics are ineffective. For example, if the endogenous creatinine clearance is less than 10 ml/min, then renal replacement therapy should be considered. In addition, endogenous creatinine clearance is also used as a reference indicator of success after renal transplantation.