Tests of adrenal reserve
Key points
- ACTH (Cortrosyn) stimulation test measures the ability of the adrenal cortex to respond to ACTH by producing cortisol appropriately.
- Blood measurements of cortisol are obtained - 1 before and 1 or more after injection of ACTH.
- Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand.
- The area is cleansed with antiseptic and punctured with a sharp needle or a lancet.
Alternative names
ACTH (Cortrosyn) stimulation test
Definition
ACTH (Cortrosyn) stimulation test measures the ability of the adrenal cortex to respond to ACTH by producing cortisol appropriately. ACTH is a hormone produced in the pituitary gland that stimulates the adrenal glands.
How the test is performed
Blood measurements of cortisol are obtained - 1 before and 1 or more after injection of ACTH.
Adult or child:
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to fill with blood. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. The tourniquet is then removed to restore circulation. After blood has been collected the needle is removed, and the puncture site is covered to stop any bleeding.
Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.
Once the blood has been collected, a needle is used to inject Cortrosyn, and additional timed specimens are collected.
Along with the blood tests, sometimes a urinary free cortisol test or urinary 17-ketosteroids may also be measured. The urine is collected over a 24-hour period.
How to prepare for the test
You may need to limit activities and eat a high-carbohydrate diet 12 to 24 hours before the test. You may be asked to fast for 6 hours before the test.
Infants and children:
The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For general information regarding how you can prepare your child, see the following topics:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.