The main cause of renal anemia is chronic renal insufficiency, or even a decrease or deficiency of erythropoietin due to renal failure. Therefore, the examination of renal anemia is mainly based on the degree of kidney damage, so the main examination of renal function, the most obvious manifestation of renal function is the increase of serum creatinine and the decrease of blood clearance rate. Secondly, routine blood tests should be performed to determine whether the patient is anemic or not, paying attention to the content of red blood cells and hemoglobin in the routine blood tests.