Blood can be drawn to check for many diseases, depending on the items for which the blood is drawn. For example, routine blood tests can check for diseases such as anemia and infections, and can also detect leukemia. Liver function can check whether there is any liver function damage, and can also reflect whether there is any bile duct obstruction and so on. Lipid test can check whether there is high blood fat, check kidney function can also see whether there is hyperuricemia, whether there is renal insufficiency, renal failure and so on. Thyroid function can reflect whether there is hyperthyroidism, hypothyroidism. Electrolytes can reflect whether there are electrolyte disorders, such as hyperkalemia, hypokalemia, hypernatremia, hyponatremia, hypercalcemia. Tumor markers can also be checked to reflect whether there is a potential risk of tumors in the body. Blood can also be drawn to check for blood sugar and to check for diabetes. There are a lot of items that can be checked, and a lot of diseases that can be reflected. However, blood tests are sometimes not the gold standard, and need to be used in conjunction with other tests and the patient’s symptoms to diagnose the disease.