Low-dose and high-dose variations of the<unk>  exist. The<unk>  is given at low (usually 1–2 mg) and high (8 mg) doses of<unk> , and the levels of cortisol are measured to obtain the results. A low dose of<unk>  suppresses cortisol in individuals with no pathology in endogenous cortisol production. A high dose of<unk>  exerts negative feedback on pituitary neoplastic ACTH-producing cells (Cushing's disease), but not on ectopic ACTH-producing cells or adrenal adenoma (Cushing's syndrome). Dose A normal result is a decrease in cortisol levels upon administration of low-dose<unk> . Results indicative of Cushing's disease involve no change in cortisol on low-dose<unk> , but inhibition of cortisol on high-dose<unk> . If the cortisol levels are unchanged by low- and high-dose<unk> , then other causes of Cushing's syndrome must be considered with further work-up necessary. After the high-dose<unk> , it may be possible to make further interpretations. Cortisol ACTH† Interpretation is suppressed by low or high doses Undetectable or low Primary hypercortisolism is likely; Cushing's syndrome, not disease (i.e., the hypercortisolism is not driven by ACTH hypersecretion) is not suppressed by low doses, but is suppressed by high doses Normal to elevated but not in hundreds Cushing's disease should be considered because the pituitary still retains some feedback control. A pituitary MRI would be needed to confirm. is not suppressed by high or low doses Elevated in hundreds Ectopic ACTH syndrome is likely. If an adrenal tumor is not apparent, a chest CT and abdominal CT is indicated to rule out a different tumor secreting ACTH. †ACTH as measured prior to dosing of<unk>  Equivocal results should be followed by a corticotropin-releasing hormone stimulation<unk> , with inferior petrosal sinus sampling.
Dexamethasone suppression test
ACTH stimulation test
Testosterone-cortisol ratio
Free androgen index
Thyroid hormone binding ratio
Combined rapid anterior pituitary evaluation panel
Cortisol awakening response
Hypophysectomy