Blood test is a relatively common test method, the body appears abnormal usually to carry out blood tests, in the medical application is more common. There are also many precautions before the blood test, you can not eat before the blood test, generally fast for more than eight hours, in the day before the test can be normal dinner, but not too greasy, do not eat anything in the morning after waking up, and can not drink water. Before the blood test also pay attention to the first three days can not eat too much greasy, also can not drink a lot of alcohol. It is best to take blood before nine in the morning on an empty stomach, too late will have an impact on the physiological endocrine hormones in the body, and the results of the blood test will be affected, try to wear loose clothing during the blood test to avoid pressure on the veins in the arms. If the symptoms of weakness, dizziness and dizziness appear after the blood test, you can drink a small amount of sugar water, which can effectively relieve such symptoms. To ensure the accuracy of the blood test results, be sure to choose a public hospital.