Somatomedin C is another name for the test for IGF-1, or insulin-like growth factor 1. It could be applied to identify GH (growth hormone) insufficiency. The test calculates the bloods level of insulin-like growth factor-1. IGF-1, a hormone, works in conjunction with growth hormone to support healthy bone and tissue development. The hormone has anabolic effects on adults and is important for childhood growth. The bodys IGF-1 levels are related to GH levels, so the test can be used to identify a variety of issues caused by either too much or too little GH.