A 57-year-old female presented with easy bruising, hirsutism, and weight loss. Morning serum cortisol was 54.1 mcg/dL (reference interval (RI): 7-25 mcg/dL) with an adrenocorticotropic hormone (ACTH) of 35 pg/mL (RI: 7-63 mcg/dL). Following a high-dose dexamethasone suppression test, cortisol was 4.1 mcg/dL with an ACTH of 17 pg/mL. Inferior petrosal sinus sampling following administration of corticotropin-releasing hormone was performed. At baseline, the central-to-peripheral ACTH gradient was 2.8-to-1. After administering CRH, this central-to-peripheral ACTH ratio was 23-to-1.
|Kornelia Galior, Ph.D.
Fellow, Clinical Chemistry
|Stefan Grebe, M.D., Ph.D.
Consultant, Clinical Chemistry
Professor of Laboratory Medicine and Pathology
Mayo Clinic College of Medicine