There is no best way to rule out leukemia, and it needs to be judged according to the clinical symptoms of leukemia combined with the results of laboratory tests. First of all, see if there are leukemia symptoms. Acute leukemia symptoms are mostly manifested as sudden onset of high fever or bleeding, accompanied by anemia, enlarged lymph nodes, bone pain, etc. Chronic leukemia usually progresses slowly. Chronic leukemia usually progresses slowly, and may include pallor, enlarged lymph nodes and spleen, and excessive menstruation in women. Laboratory tests include blood tests for abnormal levels of platelets, white blood cells, abnormal white blood cell ratios or counts, and white blood cell classification for primitive or naïve cells. Bone marrow aspiration to obtain a bone marrow picture can confirm the diagnosis, and after the aspiration, a bone marrow fluid biopsy can be done to find leukemia cells. If leukemia is suspected and cannot be ruled out by the above methods, immunophenotyping tests can also be done to rule out leukemia. If there is any discomfort, it is recommended to improve the tests under the guidance of a doctor.