Glucagon test

Investigation Protocol

Indication

Assessment of ACTH and/or growth hormone reserve when insulin stress test is contraindicated.

Preparation and precautions

This test is unreliable in patients with diabetes. The referring physician may wish to reconsider the test and advise about the patient’s diabetic medication. The patient should be euthyroid (only proceed if the free thyroxine is within the reference range) and have a 9am cortisol above 100 nmol/l within three months of the test.

If the 9am cortisol is below 100nmol/l, there is no need to perform the test for ACTH reserve, and it will only be performed for GH. In that case patients must be on their usual hydrocortisone replacement therapy, which should not be interrupted.

Patients should be fasting from midnight (water only). Warn the patient that they may well feel nauseated for the first part of test.

Procedure

Insert a cannula gauge 20 with a three-way tap, and using a syringe or the vacutainer connector system, fill one plain clotted bottle for cortisol and/or growth hormone, and one fluoride oxalate for glucose. Label with patient identification, date and write time=0 minutes.

Give intramuscular Glucagon 1mg for adults weighing less than 90kg or Glucagon 1.5mg for adults weighing more than 90kg.

Take further blood samples into bottles as above at 30, 60, 90, 120, 150, 180, 210 and 240 minutes. Mark the patient’s details, date and time of samples on each bottle. Each time samples are taken, flush the cannula with 2mls 0.9% sodium chloride and prior to taking blood samples, withdraw 2mls and discard to remove any trace of the sodium chloride flush.

The patient should remain fasting during the test but can sip water.

The cannula is removed after the test and patient should be offered a meal before going home.

Note: This test can cause nausea and vomiting at about the three hour point. It is therefore advisable that the patient is on a couch or bed during the test where they may rest should this occur.

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Patient information sheet

Glucagon test

Your doctor has referred you for a glucagon test to measure your cortisol (steroid) and/or growth hormone levels after stimulation. These hormones are controlled by the pituitary gland.

Please come fasting, i.e. nothing to drink from midnight except sips of water. You will be offered a drink and something to eat at the end of the test. Smoking should also be avoided on the day of the test but please take all your medication as normal.

During the test blood samples will be taken at half hourly intervals over a four hour period. To allow this to happen easily with the minimum of discomfort for you, we will be inserting a small tube (a cannula) into a vein in your arm at the start of the test. After some baseline samples of blood have been taken, you will be given an injection of glucagon, which will stimulate your body to release cortisol and growth hormone so it can be measured. You will be able to relax in reclining chair in the unit.

Glucagon can cause nausea and occasionally vomiting during the third hour of the test. Most people have recovered by the end of the test. However if you are still feeling unwell you will be able to stay in the department until staff are happy for you to go home. In view of this it would probably be best to have someone drive you to and from this appointment. You should expect your stay at the hospital to last at least four and a half hours.

You may wish to bring a book or magazine to read. We do have a radio, or you can access Patientline; alternatively you may like to bring your own personal radio/cd player (please bring your own headphones). You may bring someone to stay with you during the test but there is not enough space for more than one person.

Children are discouraged, as this can be disruptive to other patients. However, if this poses a particular problem for you please discuss this with the senior nurse in the unit. You should be able to undertake normal activities soon after the test is finished but we recomend that you do not drive yourself home immediately afterwards.

If you have any queries about the test, please contact

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