The high white blood cells of 20,000 need to be further clarified with clinical manifestations and other examination and laboratory tests, such as: whether there is fever, cough, coughing, diarrhea, abdominal pain, urinary urgency, urinary frequency, painful urination and other manifestations of infection, need to further improve the chest CT, abdominal ultrasound and other examinations, laboratory tests such as C-reactive protein, calcitoninogen, urinalysis, stool routine, various cultures and other laboratory tests, if the diagnosis of infection, should be given anti-infection treatment. If the patient has rheumatic diseases that cause elevated leukocytes, the patient should be treated for the original disease. If the patient has elevated leukocytes and primitive and naive cells are seen in the peripheral blood, acute leukemia should be alerted, but the latter is generally significantly higher than 20,000 elevated leukocytes. If there is severe trauma, surgical trauma, acute pancreatitis, myocardial infarction, etc., the primary disease should be treated and anti-infective therapy should be administered as appropriate. If there are acute blood loss manifestations such as liver and spleen rupture or acute hemolysis manifestations such as yellowing of skin mucosa and soy sauce-colored urine, hemostasis and treatment of hemolysis should be actively given. Some malignant tumors may have increased leukocytes and may be treated with anti-tumor therapy as appropriate.7. Understand the history of exposure to certain drugs and toxins, such as epinephrine, catecholamines, glucocorticoids, lithium salts and other applications, and discontinue them as appropriate .