In many cases, changes on routine screening tests, including the complete blood count, biochemistry profile, and urinalysis, will trigger the suspicion of Addison's disease. Chest x-rays may reveal a reduced heart size and esophageal enlargement. An electrocardiogram may show changes if the potassium concentration is elevated.
A definitive diagnosis depends on the results of a test of adrenal gland function called the ACTH stimulation test. Serum concentrations of cortisol, one of the main hormones produced by the adrenal gland, are measured before and after the administration of either synthetic or natural ACTH. Measurements of another hormone called aldosterone, which helps regulate the sodium and potassium balance, also can be checked, although this procedure is fairly uncommon. Measurement of aldosterone may be helpful in distinguishing primary failure of the adrenal glands from secondary adrenal gland failure due to abnormalities in the hypothalamus or the pituitary gland. Similarly, measurement of yet another hormone, called adrenocorticotropic hormone, also may be used to distinguish between primary and secondary adrenal failure.
