Fasting Insulin Test

This test measures the level of insulin in plasma after fasting for at least 8–12 hours. This measurement reflects the baseline level of insulin secretion from pancreatic beta cells in the absence of glucose stimulation from food. It is primarily used in conjunction with fasting glucose (FPG) testing to calculate the HOMA-IR (Home Insulin Resistance Assessment Model) index, a common tool for diagnosing insulin resistance. Elevated fasting insulin indicates that the pancreas is working overtime to maintain normal blood sugar levels, a sign of insulin resistance.