Glucose is the primary blood sugar used by cells to make energy. Insulin, a hormone secreted by the pancreas that delivers glucose to cells throughout the body. After every meal the pancreas respond by releasing insulin to transport the glucose into the cells. High blood glucose levels are associated with diabetes, neuropathy, eye problems, heart disease and stroke. Optimal range for fasting blood glucose is 70-85 mg/dL. An 8 to 12 hour fast is required for this blood test. However, drink plenty of water and take medications as prescribed.