Leukocyte 2.49×10⁹/L is lower than the normal reference value, which is more serious if bone marrow abnormality occurs, and is usually easy to cure and not considered serious if it is caused by general pathogenic infections, lack of hematopoietic raw materials, and so on. Normal adult leukocyte reference value is (4~10)×10⁹/L, while 2.49×10⁹/L is lower than the normal level, which may be related to the decrease of production, destruction or excessive consumption, distribution abnormality and other reasons. Generally, abnormal bone marrow hematopoiesis is caused by ionizing radiation, chemical poisons, etc.; and leukopenia caused by leukemia, multiple myeloma and other malignant hematological diseases is more serious and difficult to treat. Vitamin B₁₂, folic acid deficiency, viral and bacterial infections are generally not serious and can be cured after active treatment. However, there are some pathogens that cause leukopenia after infecting the human body, which is more serious and incurable, such as HIV. When the white blood cells are lowered, it is necessary to clarify the cause of the disease under the guidance of a doctor and actively treat it.