Creatinine 104.5 μmol/L is near the upper limit of normal or mildly elevated. Typically, normal serum creatinine ranges from 53 to 106 μmol/L in men and from 44 to 97 μmoI/L in women, with creatinine 104.5 μmoI/L being near the upper limit of normal, with mild elevation suggested by older patients or those with low muscle mass. Creatinine is the metabolic end product of creatine in muscle tissue. Creatinine does not bind to protein in the blood and can pass freely through the glomerulus, making it the most commonly used indicator to indirectly reflect glomerular filtration function. When the renal parenchyma is damaged and the glomerular filtration rate is reduced to a critical point (when the glomerular filtration rate is reduced to 1/3 of normal), the blood creatinine concentration will rise significantly. Although creatinine 104.5 μmol/L is within the normal range or mildly elevated, it is recommended to improve the urine routine, urinary ultrasound and other tests to rule out renal diseases, such as nephritis, kidney stones, pyelonephritis, etc., patients with these diseases may have normal or mildly elevated blood creatinine. If patients find abnormal creatinine, it is recommended to go to regular hospitals in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.