There are two aspects of leukocyte abnormalities: First, the abnormal number of leukocytes: the normal number of leukocytes, adults is 4000-10000/mL, higher than 10000/mL is leukocytosis, commonly seen in various inflammatory diseases, organism injury, hemolysis, acute poisoning, as well as hot weather, cold, emotional excitement, and after strenuous exercise. Leukopenia can be seen in viral infections as well as after radiotherapy and chemotherapy, which can lead to leukopenia; second, abnormal leukocyte ratios: abnormal leukocyte ratios refer to abnormal ratios of each of the five types of leukocytes, such as increased or decreased proportions of neutrophils, increased or decreased proportions of lymphocytes, increased or decreased proportions of eosinophils, and monocytes, basophils Each type of leukocyte increase or decrease represents a different clinical significance and can provide useful diagnostic information for clinical diagnosis.