The overnight metyrapone test
should be used to make the definitive diagnosis of HPAS.
Metyrapone Test. Metyrapone inhibits the activity of 11[beta]-hydroxylase enzyme that converts precursor to cortisol, resulting in decreased cortisol secretion and a compensatory increase in ACTH levels, as well as 11-deoxy-cortisol (the precursor of cortisol) and its urinary metabolites.
Comparison of overnight metyrapone test to either low-dose or high-dose ACTH test," Hormone Research, vol.
Significance of low-dose and standard-dose ACTH tests compared to overnight metyrapone test
in the diagnosis of adrenal insufficiency in childhood.
Once suspected, the definitive diagnosis can be confirmed by laboratory evaluation of adrenocortical function by short synacthen test, insulin tolerance test and metyrapone test
. The established reference test for the assessment of the hypothalamo-pitutary adrenal axis is to measure the cortisol response to insulin induced hypoglycemia3.This test is unpleasant for the patient, potentially dangerous, resource intensive and contraindicated in patients with ischemic heart disease and epilepsy4.
Investigation of the hypothalamo-pituitary-adrenal axis (HPA) by 1 microg ACTH test and metyrapone test
in patients with primary fibromyalgia syndrome.
The metyrapone test
and the stimulation test with CRH are contacted for the differential diagnosis from pituitary or adrenal tumours.
* Understand endocrine tests of hypothalamic-pituitary function (cosyntropin test/rapid ACTH stimulation test, insulin hypoglycemia test, metyrapone test
, levodopa test, arginine infusion test, glucose-GH suppression test, TRH test, gonadotropin-releasing hormone (GnRH) test, clomiphene test, corticotropin-releasing hormone (CRH) test, gonadotropin-releasing hormone test, water deprivation test, saline infusion test, and water loading test).
With the exception of eight who were frankly hypocortisolaemic (as defined by an early-morning serum cortisol level <83 nmol/L), all were assessed by the overnight metyrapone test (ONMTPT).
The short metyrapone test: Comparison of the plasma ACTH response to metyrapone and insulin-induced hypoglycaemia.
The low dose ACTH stimulation test is less sensitive than the overnight metyrapone test
for the diagnosis of secondary hypoadrenalism.