The blood cell analysis test mainly includes red blood cells and hemoglobin, white blood cells, platelets and related parameters. Clinically, the main purpose of hematocrit examination is to determine the presence of infections and blood system related diseases. The items and main contents of blood cell analysis are as follows: 1. Red blood cells and hemoglobin: The determination of red blood cells and hemoglobin can help diagnose whether the body has red blood cell-related diseases. For example, increased red blood cells and hemoglobin are often caused by severe vomiting, diarrhea, profuse sweating, extensive burns, or chronic hyperalgesia, uremia, hyperthyroidism crisis, diabetic ketoacidosis, and true erythrocytosis; decreased red blood cells and hemoglobin are common in infants and children under the age of 15, as well as in some elderly people and women in the middle and late stages of pregnancy. It may also be caused by various kinds of anemia, such as iron deficiency anemia, megaloblastic anemia, etc.; 2. Leukocytes: leukocytosis is common in acute infections, severe tissue injury, acute hemorrhage, acute poisoning, and leukemia; leukopenia is common in infections, such as gram-negative bacillary infections, and hematologic and immunologic disorders, such as aplastic anemia, paroxysmal sleep hemoglobinuria, bone marrow metastatic carcinoma, etc.; 3. Platelets: thrombocytopenia is common in radiation injury, acute leukemia, immune thrombocytopenia, systemic lupus erythematosus, upper respiratory tract infection, neonatal thrombocytopenia, disseminated intravascular coagulation, congenital thrombocytopenia, etc.; thrombocytosis is common in true erythrocytosis, primary thrombocytosis, chronic myeloid leukemia, and Acute infection, etc.