The normal value of 24-hour urinary creatinine is 7-18 mmol. creatinine is a product of muscle metabolism, which includes our own muscle and exogenous intake of various lean meats. After these muscles are metabolized, blood creatinine is formed, and after the blood creatinine is filtered by the kidneys, urine creatinine is formed. Elevated urine creatinine is generally related to enhanced muscle metabolism, such as whether the patient has had strenuous exercise, whether there is fever and hunger and so on. In some chronic wasting diseases, when blood glucose and fat are almost consumed, muscle is consumed, which can also cause an increase in urine creatinine. And lower urine creatinine is usually seen in renal failure, which is caused by the decrease of detoxification ability of the kidneys. But clinically it is inaccurate to judge the disease only by looking at urine creatinine without observing blood creatinine. Therefore, when abnormal urine creatinine is found, it must be combined with the blood creatinine value to make a comprehensive judgment.