The routine blood test can be used to check leukemia, but it needs to be combined with other tests to confirm the diagnosis. 1. By drawing blood for routine blood test, it can initially understand the changes in the number of red blood cells, neutrophils, lymphocytes and other major blood cells in the blood, and if there is a decrease in the number of multiple blood cells, it may be due to leukemia. 2. However, the routine blood test can only be used to make a preliminary judgment of leukemia. To understand the type of leukemia and the severity of the disease, bone marrow aspiration should be done for further blood pathology examination. If there are abnormal symptoms such as low-grade fever, nosebleeds and recurrent colds, it is necessary to consult a doctor in time for appropriate auxiliary tests to clarify the cause of the disease. If the blood count is abnormal, it is necessary to conduct other tests such as blood biochemistry and immunophenotyping besides bone marrow aspiration in order to make a clear diagnosis and to help determine the treatment plan for the later stage. Specific diagnosis and treatment should be carried out under the guidance of physicians.