Anemia means that the red blood cells and hemoglobin are lower than the lower limit of the normal range, and the degree of anemia can also be divided according to the specific value of hemoglobin. If the hemoglobin is below the normal range, it is still more than 90 grams per liter for mild anemia; if the hemoglobin is more than 60 grams per liter but less than 90 grams per liter, it is moderate anemia; if the hemoglobin is more than 30 grams per liter but less than 60 grams per liter, it is severe anemia; if the hemoglobin is less than 30 grams per liter, it is extremely severe anemia. For patients with severe anemia, they often have a series of clinical symptoms such as dizziness, headache, dizziness, fatigue, chest tightness and asthma after activities, and need red blood cell infusion for support treatment. It is more important to improve the examination of anemia patients, identify the causes of anemia, and treat the causes.