Indication

Assessment of ACTH/cortisol and growth hormone reserve.

Contraindications

Severe cortisol deficiency, (serum cortisol <100nmol/L) unless treated with hydrocortisone, patient not eaten for two days or more, glycogen storage diseases.

Procedure

1. The patient should be fasted from midnight.
2. Weigh the patient.
3. Insert an intravenous cannula and wait 30 minutes. The patient should be at rest.
4. Take blood for growth hormone, IGF-1 and cortisol estimations (gold top vial with gel), glucose (grey top vial).
5. Give
   1. 1mg Glucagon subcutaneously in adults <= 90kg.
   2. 1.5mg Glucagon subcutaneously in adults > 90kg.
6. Take blood at 30, 60, 90, 120, 150, 180 minutes for glucose, growth hormone and cortisol estimations. Do not request cortisol if patient is taking hydrocortisone.

Interpretation Guidelines

Normal response

• Glucose: usually rises to a peak around 90 min and then falls
• Cortisol: rises by more than 180nmol/L to above 580nmol/L
• Growth hormone: rises to above 20mU/L (10 - 20mU/L equivocal)

Notes:

1. This test may substitute for insulin stress test where the latter is contra-indicated.
2. The test is not suitable for use in diabetes due to its unreliable stimulatory effect in this condition.
   Patients should have eaten normally for at least 48hr before the fast.
3. 20% normal patients fail to respond.