This is a blood test to check for diabetes. If you have diabetes, your body doesn't make enough insulin to keep your blood sugar in check. This means your blood sugar levels are too high, and over time this can lead to serious health problems including heart, nerve, kidney, and eye damage. Postprandial means after a meal. This test is done to see how your body responds to sugar and starch after you eat a meal. As you digest the food in your stomach, blood glucose, or blood sugar, levels rise sharply. In response, your pancreas releases insulin to help move these sugars from the blood into the cells of muscles and other tissues to be used for fuel. Within 2 hours of eating, your insulin and blood glucose levels should return to normal. If your blood glucose levels remain high, you may have diabetes.