The blood test for anemia does not require fasting. In fact, fasting is mainly to exclude the effect on blood sugar and blood lipids, and has little effect on other indicators. Therefore, fasting is not required for routine blood tests. When you come to the emergency room, for example, you need to do blood tests for fever, the doctor will not ask the patient if he or she has eaten. Only when doing metabolism-related items such as blood glucose, blood lipids, and biochemical blood uric acid, fasting is required. The physical examination mainly requires fasting only for biochemical tests. In addition, checking tumor markers, thyroid function or immune function, such as the function of T-lymphocytes and immunoglobulins, do not require fasting. So not all visits to the hospital or blood draws require fasting, but it is also important not to eat excessively large fish and meat and other high-fat, high-purine foods, which can cause an increase in blood viscosity and thus have an impact on blood tests. A normal diet, or even a lighter diet, is recommended.