Creatinine measurement is used to evaluate kidney function, which is the so-called ability of the kidneys to detoxify the body. When assessing kidney function it is necessary to select a substance that is metabolized by the kidneys but not absorbed and secreted by the kidneys, and creatinine meets such a requirement and is therefore a very desirable indicator used clinically to assess kidney function. The normal value of creatinine is between 30 and 110 μmol/L. If it exceeds 110 μmol/L, it is called renal failure, and the cause of renal failure should be found. Acute renal failure is mainly due to the application of nephrotoxic drugs, such as a large number of drugs such as ibuprofen. Chronic renal failure is mainly caused by chronic kidney diseases, such as diabetic nephropathy, hypertensive nephropathy and so on. Here we need to emphasize that the value of creatinine is easily affected by gender, age, weight and other factors, so we can combine these factors to calculate the glomerular filtration rate, which is more accurate than creatinine.