American Association of Critical-Care Nurses (AACN) Certification Practice Test

How is Addison's disease primarily diagnosed?

1. CT scan

2. ACTH stimulation test

3. Blood sugar test

4. Thyroid function test

The correct answer is: ACTH stimulation test

Addison's disease is primarily diagnosed using the ACTH stimulation test. This test measures the adrenal glands' response to adrenocorticotropic hormone (ACTH). In a healthy individual, administration of ACTH stimulates the adrenal glands to produce cortisol. In patients with Addison's disease, where there is an insufficiency of cortisol due to adrenal gland damage or dysfunction, the cortisol levels will not rise appropriately after the administration of ACTH. While imaging tests like a CT scan can help evaluate the adrenal glands, they do not directly diagnose the functional aspect of Addison's disease. Blood sugar tests are not specific to diagnosing Addison's disease, as they assess glucose levels rather than adrenal function. Thyroid function tests evaluate the thyroid gland, which is not directly related to the diagnosis of Addison's disease. Thus, the ACTH stimulation test stands out as the most relevant and specific diagnostic tool for assessing adrenal insufficiency in suspected Addison's disease.