15th September 2024

Investigations

Both insulin and glucagon stimulate GH and tests have derived from giving these hormones and measuring a lack of GH level rise. The insulin stress test and glucagon stimulation test are widely used methods to assess GH reserves, unless there are contraindications to insulin or glucagon use such as epilepsy, ischemic heart disease, untreated hypothyroidism or basal cortisol levels below 100 nmol/l. The growth hormone-releasing hormone test, also known as the arginine stimulation test, serves as a 2nd line option for those where the insulin tolerance and glucagon tests are contraindicated.

Low IGF-1 levels support the diagnosis of GH deficiency, but normal IGF-1 levels do not exclude it. A pituitary MRI should be performed to rule out a pituitary tumour that could be compressing GH-producing cells and causing GH deficiency.