The blood routine of tumor patients will be abnormal in most cases, but there are some tumor patients with normal blood routine. In the case of solid tumors such as lung cancer and breast cancer, the blood routine in the early stage of the tumor is usually normal, just like normal people, with no changes. When the tumor progresses to advanced stage, especially when it is complicated by infection, changes such as increased white blood cell count will occur. When malignant tumor cells metastasize to the bone marrow, the normal hematopoietic function is inhibited, and the blood routine will show changes such as decreased red blood cells, white blood cells and platelets. However, for hematologic malignancies, such as acute leukemia, two high and one low changes can be seen in the blood routine at the early stage of the disease, i.e., the white blood cell count is increased, while the red blood cell and platelet counts are decreased, and most patients come to the clinic because of these abnormal changes in the blood routine.