To determine the kidney function, blood creatinine test and endogenous creatinine clearance test are often used in hospitals. If blood creatinine exceeds normal value and endogenous creatinine clearance is lower than normal value, it is called renal insufficiency. Endogenous creatinine clearance is more accurate when diet and other factors are excluded. In addition, the increase of blood urea nitrogen, uric acid and cystatin C can also reflect renal insufficiency. Of course, if you want to judge the acute or chronic renal insufficiency, you have to combine the length of history of kidney disease, the size of the kidneys, the presence of anemia and other conditions.