Glucose test is to measure your
sugar levels and you fail if your
sugar is too high. You just drink a drink, wait an hour, and then they take your blood. For the one hour one, you can fail simply because you had to much sugar the night before or that morning, so you may want to limit sugar intake before hand in order to pass. If you fail the 3 hour one, which is the follow up test, it most likely means you have gestational diabetes.