Rudas Lab - Clinical Laboratory - Χημείο Ρούδα

CRH stimulation test is used as test in both adrenal insufficiency and Cushing syndrome. In healthy persons, baseline ACTH increases two- to fourfold within 30-60 minutes of CRH administration. 

Patients with adrenal insufficiency have one of three patterns of response to CRH stimulation:

• Patients with primary adrenal insufficiency have high baseline ACTH (which increases in response to CRH), with low cortisol levels before and after CRH.
• Patients with secondary (pituitary) adrenal insufficiency have low baseline ACTH levels that do not respond to CRH. In these cases Cortisol levels are not affected by CRH.
• Patients with tertiary (hypothalamic) disease (CRH deficiency) have low baseline ACTH levels and an exaggerated and prolonged response to CRH. Serum cortisol levels in these patients typically do not reach the maximum normal range. Patients with Cushing syndrome respond to CRH with a >20% rise in cortisol and a >35% increase in ACTH. In most cases, patients with primary adrenal hypercortisolism or ectopic ACTH syndrome do not respond to CRH.