The test for insulin-like growth factor-1 (IGF-1) is also known as Somatomedin C. It may be used to detect growth hormone (GH) deficiency. The test measures the level of insulin-like growth factor-1 in the blood. IGF-1 is a hormone which along with growth hormone helps promote normal bone and tissue growth and development. The hormone plays a significant role in childhood growth and has anabolic effects in adults. The IGF-1 levels are associated with the level of GH in the body, so the test can be used to diagnose many problems linked to too much or too little GH.