The number of monocytes alone cannot be used as a basis for clinical diagnosis of leukemia. For example, acute monocytic leukemia should be diagnosed as acute monocytic leukemia only when the number of primitive monocytes and naïve monocytes are added to ≥80%. Patients with acute monocytic leukemia may present with a ratio of ≥ 30% of primitive and naïve monocytes, while for other types of leukemia, the number of monocytes is not diagnostic. Patients with leukemia usually have symptoms such as pale skin and mucous membranes, malaise, fever, and bleeding from various parts of the body such as the nose and gums, and the bleeding usually does not stop easily. When these symptoms occur, it is recommended to seek medical examination, which usually requires routine blood tests, biochemistry, bone marrow aspiration biopsy, and chromosome karyotype to further confirm the diagnosis. If leukemia is diagnosed, treatment can be based on specific staging, such as molecularly targeted therapy with imatinib, immunotherapy with rituximab, or a combination of chemotherapy, radiation therapy and hematopoietic stem cell transplantation. There is no need to worry when the monocyte test is normal or decreased, it is a normal phenomenon. When laboratory tests show an increase in monocytes, it may be caused by infections such as tuberculosis, typhoid, or malaria, in addition to leukemia. You should take into account other symptoms and diagnostic tests, actively fight against infection or apply anti-tuberculosis drugs, and at the same time, get enough sleep, avoid smoking and drinking alcohol, and eat more vegetables and fruits to supplement vitamins.