What Are Blood Glucose Levels? Blood glucose levels, often referred to as blood sugar levels, measure the amount of glucose (sugar) present in the bloodstream. Glucose is the primary source of energy for our cells and is vital for overall health. These levels are constantly regulated by the body to ensure they stay within a specific range. Fasting blood glucose levels are measured after an overnight fast and are typically in the range of 70 to 100 milligrams per deciliter (mg/dL) for individuals without diabetes. Postprandial blood glucose levels, which are measured after meals, can temporarily rise but should return…