If your doctor is evaluating your adrenal health, the doc will likely order and evaluate blood and urine tests to measure your cortisol levels. (Cortisol has anti-inflammatory properties, helps regulate blood glucose levels, and helps regulate blood pressure.)
Just because a blood or urine test comes back normal doesn't mean that adrenal fatigue isn't present. Some people believe that salivary testing is the way to go when evaluating cortisol levels and other hormone levels as well. Salivary tests provide a more accurate measurement of cortisol deficiency than blood levels do. That doesn't mean that the blood levels are without value, however.
That being said, the first test that health practitioners order is often a morning (AM) cortisol test, which is a blood test.
Basics of morning cortisol
Cortisol is the predominant hormone secreted by the adrenal glands. The morning (AM) cortisol blood test takes place at a lab around 8:00 or 9:00 a.m. — the best time to obtain a blood cortisol level, because your body normally makes (or should make) the highest amount of cortisol in the morning.
In the setting of adrenal fatigue, you'd expect that this test would show a lower than normal cortisol level. In the later stages of adrenal fatigue, you'd expect to find a very low morning cortisol level. A normal range for a blood cortisol level is 5 to 25 micrograms per deciliter (mcg/dL).
A level greater than 20 means that your adrenal glands are functioning normally. A level of less than 5 is thought to be a sign of nonfunctioning adrenal glands — the adrenal glands are making little or no cortisol.
If the test comes back with a level between 5 and 20, physicians may find the level hard to interpret — to what degree are the adrenal glands functioning? Other forms of testing need to be done to be conclusive. AM cortisol isn't a bad test, but it's just a start.
How to stimulate the adrenal glands with cosyntropin
When a morning cortisol level is between 5 and 20, doctors may order a cosyntropin stimulation test for more information. Cosyntropin is a synthetic copy of the hormone ACTH, which is normally made by the pituitary gland. This hormone stimulates the adrenal glands to make cortisol.
In this test, cosyntropin is given intravenously, and the cortisol levels are measured at 30 minutes and 60 minutes. The cosyntropin should stimulate the adrenal glands enough that the cortisol level doubles. If it doesn't, that may be a sign of absolute adrenal insufficiency.
If you have adrenal fatigue, you may still have a normal cosyntropin stimulation test. The cosyntropin can stimulate the adrenal glands for a short time to give you a normal result.
The test provides only a snapshot of adrenal gland functioning; it's too much of a short-term test to provide full value in the diagnosis of adrenal fatigue. Because the test can't completely evaluate for adrenal fatigue, you need further workups.
