Additional Specimen Instructions

Growth Hormone Suppression Test – Additional Specimen Information

The Growth hormone (hGH) suppression test is used to confirm acromegaly in patients with signs and symptoms of hGH excess. Single, random growth hormone measurements are not diagnostic because hGH is secreted episodically, typically with the onset of deep sleep. Growth hormone is suppressed by glucose and failure to suppress hGH following a glucose load is diagnostic of acromegaly (when coupled with elevated IGF1 and clinical signs of growth hormone excess).

This profile includes a baseline serum specimen and subsequent serum specimens at 60 and 120 minutes post-glucose ingestion.

Procedure

1. The patient should be fasting for 8-12 hours prior to the start of the test.
2. Draw a gold top tube for a baseline (0 min) serum hGH.
3. Give the patient 75 grams of glucose and instruct the patient to drink the entire volume.
4. Begin timing once the patient has finished the drink.
5. Draw additional gold top tubes at 60 and 120 minutes after the patient has finished the drink.