How can I test adrenal function?
One way to test adrenal function is to measure the hormones that the adrenal glands make. The most common hormone that we can measure is cortisol which can be measured in blood, saliva or urine. Because cortisol is released in a circadian pattern throughout the day, multiple checks might be needed to fully assess adrenal function.
There are certain types of severe adrenal dysfunction that require measuring aldosterone and renin (the two hormones that keep the balance of sodium and potassium in the blood). This test is usually done if you have high blood pressure and good reason to suspect primary adrenal insufficiency.
Sometimes medical doctors will perform an ACTH stimulation test. ACTH, or AdrenoCorticoTropin Hormone, is the hormone that comes from the pituitary gland and is involved in the HPA axis that controls adrenal function. In a healthy person ACTH will stimulate the adrenal glands to produce cortisol. By measuring baseline cortisol levels, then giving a shot of ACTH and then re-measuring cortisol we can see if the adrenals are responding properly. Conversely sometimes medical doctors will perform a dexamethasone suppression test. Giving dexamethasone should lower cortisol levels. This test is used to further evaluate people who have high cortisol.
Naturopathic doctors frequently use salivary cortisol testing to evaluate adrenal function. The patient will collect four samples of saliva throughout the day. These samples will show the circadian rhythm of cortisol. It should be highest in the morning and then slowly drop down through the day. In addition, these tests often measure DHEA, one of the androgens produced by the adrenal glands. Cortisol has an inverse relationship to DHEA.
(Edited Oct 2017, I am now using a dried urine test to measure cortisol throughout the day.)
Currently most allopathic medical doctors do not recognize this more “mild” but still disabling type of adrenal dysfunction. They do recognize a serious acute adrenal insufficiency also known as Addison’s disease.
Please know that when you ask your medical doctor to check your adrenal function, he or she is most likely only going to rule out this serious type of dysfunction and won’t address “adrenal fatigue” which I see regularly in my practice.