Low urine creatinine is not harmful to the body if the blood creatinine remains within the normal range. If the urine creatinine is lowered while the blood creatinine is already elevated, it may develop into uremia. Urine creatinine is detected by the excretion of creatinine in blood through urine. If urine creatinine is reduced and blood creatinine is still within the normal range, this situation suggests that the kidney detoxification ability of the patient is still normal and does not require special treatment and is not harmful to the body. If the patient’s urine creatinine is lowered, and the creatinine in the blood has already increased significantly, it means that the decrease in urine creatinine is caused by the decrease in the detoxification ability of the kidneys, so this situation is more dangerous and has the possibility of developing into uremia. Of course, there are a few cases where the decrease of creatinine in urine is caused by muscle atrophy in the body, because creatinine is a product of muscle metabolism, and when the muscle atrophy produces less creatinine, so the creatinine in urine will decrease. This condition can cause the patient to gradually become difficult to walk and may involve the respiratory muscles to affect breathing.