High microscopic leukocytes are mainly indicative of infection in the body and are commonly seen in urine tests, but can also be applied to blood, secretions and human tissues. Microscopy is a diagnostic approach that uses a microscope to magnify and observe human excretions, secretions, exfoliated cells and human tissues. When an infection or trauma occurs, leukocytes will gather in large numbers and exert their immune utility.1. Urine microscopy: High leukocytes suggest urinary tract infection. As bacteria and viruses cause infections in the urethra, bladder, ureter and other parts of the body, as well as conditions such as nephritis and prostatitis, causing a large aggregation of white blood cells, which are discharged through the urine and can be seen under the microscope. Patients can manifest as frequent urination, urgency and painful urination. In addition, inflammation of the reproductive system in men and women can also cause high leukocytes in urine microscopy due to secretions mixed in the urine; 2. Blood microscopy: high leukocytes can have a variety of causes, first of all, infectious diseases can cause high leukocytes, such as abscess, appendicitis, measles, etc. Some other conditions, such as myocardial infarction, burns, trauma, poisoning, diabetes, etc., can cause an increase in the number of white blood cells. With the development of medicine, microscopy for blood has now been gradually replaced by instruments that can count the number of cells more efficiently and accurately; 3. Microscopy of secretions: finding an increase in leukocytes suggests infection, such as leukocyte microscopy, high leukocytes suggest gynecological infection inflammation, such as vaginitis, cervicitis, etc. Sputum microscopy suggests infectious respiratory diseases, such as bronchitis, pneumonia, etc. Cerebrospinal fluid microscopy, if leukocytosis, suggests bacterial infection, such as septic meningitis, tuberculous meningitis and other intracranial infections; 4. Other: exfoliated cells and human tissue microscopy are mainly used for pathological biopsy, and the presence of high leukocytes also suggests the presence of infectious lesions in the body, but its main function is to carry out benign and malignant identification of cancer cells.