A cortisol 45-minute test involves the administration of synthetic ACTH to stimulate cortisol production and measuring its levels 45 minutes after administration. Offering a detailed assessment of adrenal function over time, this test enables healthcare professionals to observe adrenal gland responses to synthetic stimuli and aids in diagnosing conditions like Cushing’s syndrome, adrenal hyperplasia, adrenal insufficiency, and Addison’s disease.