Whether or not a blood creatinine of 117 μmol/L in a 75-year-old man is serious depends mainly on the cause of the elevation. If the creatinine is elevated due to physiological reasons or acute kidney injury, the creatinine can return to normal after removing the influencing factors, and it is usually not serious at this time. If the creatinine is elevated due to chronic kidney disease, with the progress of the disease, it may develop into uremia, which is relatively serious. Normal serum creatinine ranges from 53 to 106 μmol/L in men and from 44 to 97 mol/L in women. Some patients with elevated creatinine may be due to their own muscle content is higher, or usually eat more meat, more exercise caused by the urine routine and urinary system ultrasound and other related examinations do not see abnormalities, clear kidney without obvious diseases, such cases are usually not serious. If the patient due to various reasons for acute kidney injury creatinine elevation, correct the reversible causes, creatinine may return to normal, this time is usually not serious; if the chronic kidney disease caused by creatinine elevation, with the progress of the disease, may develop into uremia, this time is relatively more serious. If the elderly found that the blood creatinine increased, it is recommended to go to the regular hospital in time, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.