The creatinine value of renal failure is usually above 110 μmol/L. Due to the different examination methods in each hospital, the reference value is more or less different, and some hospitals may be above 90 μmol/L, while some hospitals are above 130 μmol/L. Therefore, to determine renal failure, you need to combine the upper limit of the reference value of creatinine in the local hospital. Since creatinine is a product of muscle metabolism, the value of creatinine is easily affected by the patient’s age, weight and muscle content. For example, patients with similar kidney detoxification capacity, those who are younger, heavier and have more muscle content will have a higher creatinine value than those who are older, lighter and have less muscle content. Therefore, to exclude the influence of these factors, glomerular filtration rate is commonly used clinically to evaluate renal function, and this index is more accurate than creatinine. Once a patient is found to have elevated creatinine, he or she can be considered to be in renal failure, and the next step needs to be to clarify whether it is acute renal failure or chronic renal failure, as this is very meaningful for the patient’s prognosis.