Total leukocyte count was (4-10)*10^9/L in adults and varied in children. Absolute value of neutrophilic nuclei is (0.04-0.5)*10^9/L, lobulated nuclei is (2-7)*10^9/L, eosinophils (0.05-0.5)*10^9/L, basophils (0-0.1)*10^9/L, lymphocytes (0.8-4)*10^9/L, monocytes (0.12-0.8)*10^9/L. Consultation with a specialist is recommended. 1. Leukocytes: Adult leukocytosis refers to the total number of leukocytes higher than 10*10^9/L, leukopenia refers to lower than 4*10^9/L, influenced by the number of neutrophils and lymphocytes. 2. Neutrophil: physiological increase is seen in strenuous exercise, high temperature, etc. Pathological increase is seen in acute infection, acute hemorrhage, leukemia, etc. Neutropenia is seen in infection, physicochemical injury, etc. 3. Eosinophils: increase in allergic diseases, parasitic diseases, blood diseases, etc., decrease in typhoid fever, major surgery, etc., with little clinical significance. 4. Basophilic granulocytes: increased in allergic diseases, hematological diseases, malignant tumors, etc., decreased without significance. 5. Lymphocytes: physiological increase is seen in children, pathological increase is seen in infectious diseases, recovery from acute infectious diseases, transplantation rejection, etc., and decrease is seen in radiation injury. 6. Monocytes: increase in infections such as malaria, hematologic diseases such as mononuclear cell leukemia, decrease in hairy cell leukemia. If the total number of leukocytes and the classification of leukocytes are abnormal in routine blood tests, timely diagnosis and treatment should be made.