For any type of anemia, if the anemia is severe, there is a need for active transfusion of red blood cells to correct the anemia. However, anemia can reoccur after transfusion of red blood cells, and it is not a long-term solution. Therefore, after correcting anemia with red blood cell transfusion, it is still necessary to diagnose the specific cause of the anemia and treat it accordingly. For example, patients with iron deficiency anemia need iron supplementation, those with megaloblastic anemia need to be supplemented with folic acid and vitamin B12, and patients with acute blood loss anemia need to find the source of bleeding and receive hemostatic treatment. Anemia caused by malignant hematological disorders like acute leukemia or myelodysplastic syndromes requires anti-tumor treatment.