Specimen Type: Serum
Container: 1 Serum Separator Tube (SST)
Preferred Vol: 0.50 mL
Min Vol: 0.30 mL
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 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.