Laboratory assessment of hypothalamic-pituitary-adrenal axis function - UpToDate

The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol production. Hypothalamic secretion of corticotropin-releasing hormone (CRH) and vasopressin into the hypothalamic-pituitary portal veins stimulates the release of corticotropin (ACTH) from the pituitary gland. ACTH, in turn, promotes cortisol secretion by the adrenal cortex. Measurements of cortisol and its secretagogue ACTH are critical in the diagnostic and etiologic evaluation of hypercortisolism and adrenal insufficiency. However, laboratory measurements are influenced by many factors that can complicate the interpretation of results, including the episodic and diurnal variation in hormone secretion and the different assays used for hormone measurement. This topic will review the laboratory assessment of HPA axis function, clinical indications for these measurements, and potential pitfalls and caveats for the interpretation of test results. Detailed approaches to the diagnosis of Cushing syndrome and adrenal insuffici

The hypothalamic-pituitary-adrenal (HPA) axis regulates cortisol production. Hypothalamic secretion of corticotropin-releasing hormone (CRH) and vasopressin into the hypothalamic-pituitary portal veins stimulates the release of corticotropin (ACTH) from the pituitary gland. ACTH, in turn, promotes cortisol secretion by the adrenal cortex. Measurements of cortisol and its secretagogue ACTH are critical in the diagnostic and etiologic evaluation of hypercortisolism and adrenal insufficiency. However, laboratory measurements are influenced by many factors that can complicate the interpretation of