Poor Blood Circulation The person is made to fast until following your test is fully gone. A sample of blood will probably be come to determine the fasting blood glucose levels level. The person is going to be given a container of liquid having a known concentration of glucose inside of it. After drinking this liquid, the individuals blood will probably be drawn a minimum of a half an hour to an hour after consumption. There is also another intravenous glucose tolerance test nonetheless it is becoming antiquated as it requires the person have blood drawn, be injected using a solution of glucose, after which have blood drawn again after the test to check the blood sugar.