Glucagon testing in adult growth hormone deficiency-current status and future perspectives

Growth hormone deficiency (GHD) in adults is a recognized clinical syndrome and its diagnosis is established through GH stimulation testing. The decision to perform GH stimulation testing should be based on clinical findings, medical history and using the appropriate GH stimulation test to obtain biochemical evidence. The insulin tolerance test (ITT) remains the diagnostic test of choice, but this test is labor intensive, contraindicated in the elderly and in adults with seizure disorders and ischemic heart disease, can be unpleasant for the patient, and is potentially hazardous. The glucagon stimulation test (GST) in recent years has been increasingly used as the alternative test to the ITT in the US and Europe because of its availability, reproducibility, safety, lack of influence by gender and hypothalamic cause of GHD, and relatively few contraindications. In the article, we discuss our recommendations in performing this test, the potential drawbacks in conducting and caveats in interpreting this test, and its future perspectives.