The five routine blood tests include white blood cells, red blood cells and platelets, but it is difficult to diagnose a disease through routine blood tests alone, and the diagnosis of a disease mostly requires a comprehensive judgment of the patient’s clinical symptoms, blood tests, imaging tests, and pathological tests, etc. 1. Acute myocardial infarction, leukemia, and malignant solid tumors. Leukopenia is commonly seen in infections, aplastic anemia, hemophagocytic syndrome, partial megaloblastic anemia, severe iron deficiency anemia, systemic lupus erythematosus, etc.; 2. Erythrocytes: If increased red blood cells and hemoglobin are found by routine five blood tests, it may be due to massive burns, chronic hyperalgesia, uremia, hyperthyroidism crisis, diabetic ketoacidosis, and Erythrocytosis and other diseases. If the red blood cells and hemoglobin decrease may be due to a variety of anemia; 3. Platelets: Through the five routine blood tests, the body can be checked for platelet-related diseases. Thrombocytopenia is commonly seen in aplastic anemia, lymphoma, thrombocytopenic purpura, megaloblastic anemia, and advanced myelofibrosis. Thrombocytosis is common in patients with trauma, true erythrocytosis, myeloproliferative neoplasms, and some cancers.