Human hemoglobin is very easy to identify through professionals because normal human hemoglobin is 120-160 g/L for men and 110-150 g/L for women. if the hemoglobin reaches 187 g/L, which is obviously beyond the normal range, there must be problems with the blood system, but there will still be some difference with leukemia because the diagnosis of leukemia does not rely solely on the hemoglobin level The diagnosis of leukemia is not based solely on hemoglobin level. Leukemia is diagnosed only when leukemic cells are found and a certain percentage of leukemic cells are present. A simple hemoglobin of 187 g/L needs to be reviewed first, and if it is still 187 g/L after review, true erythrocytosis needs to be considered. True erythrocytosis and pseudo-erythrocytosis need to be differentiated, and the patient should be asked about his or her occupational history, any history of smoking, any history of lung disease, and also whether the patient is a long-term resident of the highlands. If the above factors are present, it is necessary to remove the above factors and then check whether the hemoglobin can decrease. If none of the above factors exist, the patient needs to be given a bone marrow aspiration and even genetic testing to exclude true erythrocytosis. In JAK2 positive patients, the hemoglobin is significantly higher, so the diagnosis is likely to be true erythroblastosis, which is somewhat different from leukemia.