Blood creatinine 138μmol/L suggests that blood creatinine is elevated, which can be divided into physiological and pathological factors. Physiological factors such as eating high protein diet, exercise, etc., creatinine can be restored to normal level; pathological factors include acute kidney injury and chronic kidney disease, etc., if the blood creatinine elevation caused by acute kidney injury can be restored in general, and if the elevation caused by chronic kidney disease can not be restored. 1. Physiological factors: after eating a large amount of high-protein diet, strenuous exercise, blood creatinine may have a transient increase, after controlling the diet or resting, blood creatinine will usually return to the normal level. 2. Pathological factors: acute kidney injury and chronic kidney disease. Acute kidney injury is divided into pre-renal, renal and post-renal. If the blood creatinine is elevated due to pre-renal factors such as insufficient effective circulating blood volume, vomiting, etc., the creatinine can usually return to normal after rehydration and replenishment of blood volume. If it is due to post-renal such as urinary stones, creatinine can return to normal after removing the obstructing factors. Chronic kidney disease: the causes include chronic glomerulonephritis, nephrotic syndrome, lupus nephritis and so on. It is difficult to return to normal after the blood creatinine is elevated in chronic kidney disease, and it can only be treated for the cause of the disease to protect kidney function and delay further deterioration of kidney function. Patients with blood creatinine of 138μmol/L should go to the hospital in time to clarify the cause of the disease and follow the doctor’s instructions for standardized treatment.