Routine blood test is one of the most common tests in hospitals, mainly including the following: 1. white blood cells (WBC) Normal value: adults (4.0~10.0) × 109/L Clinical significance: increase: mostly seen in bacterial infections, serious tissue damage, hemorrhage, poisoning and other stressful situations and leukemia; decrease: commonly seen in certain viral infections, blood diseases, radiation damage, hypersplenism, etc. . 2, red blood cells (RBC) male 4.0-5.5X1012/L, female: 3.5-5.0X012/L Clinical significance: Increase: (1) relative increase: vomiting, diarrhea, polyuria, extensive burns, etc.; (2) absolute increase: true erythrocytosis; (3) compensatory increase: hypoxia. Decrease: common in iron deficiency, hemolytic, aplastic anemia and acute and chronic blood loss, etc. 3. Platelets Normal value: (100~300)× 109/L. Clinical significance: Increased: common in acute infection, blood loss, hemolysis, etc.; decreased: common in aplastic anemia, thrombocytopenic purpura, hypersplenism, etc. 4, leukocyte classification (DC) Normal values: Neutrophils (N): 40% to 75% of total leukocytes, absolute value (1.80-6.30) × 109/L Eosinophils (E): percentage of total leukocytes: 0.004-0.08. Basophils (B): percentage of total leukocytes: 0.03-0.08, absolute value (0.12-0.8) × 109/L. Lymphocytes (L): percentage of total leukocytes: 20%-40%, absolute value (0.8-3.5) × 10*9/L Monocytes (M): percentage of total leukocytes 3%-8%, absolute value: (0.12-0.8) × 10^9/L Clinical significance: Neutrophils (N): same as leukocytes. Eosinophils (E): (1) increased: common in allergic diseases, parasitic diseases, etc.; (2) decreased: common in typhoid fever, early paratyphoid fever, major surgery, burns and other stressful conditions and after long-term application of adrenal glucocorticoids. Basophils (B): increased: common in leukemia, after splenectomy, and lead and zinc poisoning, etc. Lymphocytes (L): (1) increased: seen in infectious diseases caused by certain viruses or bacteria, acute and chronic blood diseases, drug reactions, metabolic reactions, etc.; (2) decreased: seen in excessive destruction of lymphocytes (such as X-ray irradiation, chemotherapy, application of adrenal glucocorticoids or lymphocyte toxins, etc.), immunodeficiency diseases, Hodgkin’s disease, etc. Monocytes (M): increased: common in infections, blood diseases, etc. Therefore, routine blood tests help doctors to detect and diagnose diseases in a timely manner, and also guide the evaluation of treatment effects.