Fasting Insulin

Overview

Overview

High fasting insulin levels are a good indicator of insulin resistance, whether or not the patient shows glucose intolerance. Insulin resistance occurs when the cellular response to the presence of insulin is impaired, resulting in a reduced ability of tissues to take up glucose for energy production. Chronically high insulin levels are seen as the body attempts to normalize blood sugar levels. The normal range for fasting insulin is 1 – 15 µIU/mL, but levels between 1 and 8 µIU/mL are optimal. Blood levels of insulin 2 hours after a meal are now becoming an important indicator of both diabetes progression and cardiovascular disease risk. In non-diabetics, elevated postprandial insulin may be a better marker of cardiovascular disease risk than fasting insulin. In individuals with diabetes, postprandial levels become lower as diabetes progresses and beta-cell responsiveness deteriorates, indicating worsening of blood sugar control. In nondiabetics, whose pancreatic beta cell function is normal, insulin levels usually return to normal (1-15 µIU/mL) within 2 hours after eating a typical breakfast meal. Elevated postprandial insulin levels have been strongly linked with coronary artery disease risk in non-diabetics.