Low IGF-1 levels are observed in Growth hormone (GH) deficiency / resistance. Elevated levels indicate a sustained overproduction of GH or excessive recombinant human Growth hormone (rhGH) injections. This assay is useful for diagnosing growth disorders and adult GH deficiency. It is also used to monitor rhGH treatment. This test is also used for diagnosis and followup of Acromegaly & Gigantism.