The Insulin Post Prandial (PP) test measures the amount of insulin in your blood. Insulin is a hormone that helps move the glucose or the blood sugar from your bloodstream into your cells. This test helps measure and evaluate the insulin production by the beta cells in the pancreas. It further helps to determine the cause of low blood sugar levels or high blood sugar levels in the body as well. This test will also help the doctor to understand whether a Type 2 diabetic patient needs extra insulin or not.