Fasting Required: No Specimen: Blood Results: 3-5 Business Days Description: An indirect measure of the average amount of growth hormone (GH) being produced by the body. This insulin-like growth factor level is used to evaluate disturbances of growth and to monitor treatment with growth hormones. Methodology Liquid Chromatography/Mass Spectrometry (LC/MS) Clinical Significance Insulin-like growth factor I (IGF-I, or somatomedin C), a protein involved in stimulating somatic growth, is regulated principally by growth hormone (GH) and nutritional intake. IGF-I is transported in serum by several proteins; this helps maintain relatively high IGF-I plasma levels and minimizes fluctuations in serum IGF-I concentrations. Measuring IGF-I is useful in several growth-related disorders. Dwarfism caused by deficiency of growth hormone (hypopituitarism) results in decreased serum levels of IGF-I, while acromegaly (growth hormone excess) results in elevated levels of IGF-I. IGF-I measurements are also helpful in assessing nutritional status; levels are reduced in undernutrition and restored with a proper diet. Alternative Name(s) Somatomedin-C, Insulin-Like Growth Factor, IGF-1