Based on creatinine 109μmol/L alone, it is difficult to determine the stage of nephropathy. It is also necessary to refer to the patient’s medical history, clinical manifestations and glomerular filtration rate to make a comprehensive judgment. Serum creatinine concentration is a commonly used method for clinical assessment of glomerular filtration function, which is fast and easy to detect, but with low sensitivity, it cannot reflect the early stage of renal damage. Meanwhile, serum creatinine concentration is also affected by gender, age, muscle mass, protein intake, and certain drugs. Therefore, it is difficult to determine the stage of kidney disease just based on one test value of creatinine 109μmol/L. Clinically, the stage of kidney disease is usually based on glomerular filtration rate, which is usually calculated by formula such as MDRD formula and CKD-EPI formula. Among them, glomerular filtration rate ≥90ml/min is stage 1, 60~89ml/min is stage 2, 30~59ml/min is stage 3, 15~29ml/min is stage 4, and less than 15ml/min is stage 5. Creatinine abnormal patients, it is recommended that early regular hospital consultation, standardized treatment under the guidance of physicians, in order to reduce the adverse effects of the disease.