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11-Deoxycortisol is the predominant deoxycorticosteroid and is the immediate precursor of cortisol. 11-Deoxycortisol is typically increased when ACTH is elevated, such as occurs in Cushing's disease and ACTH producing tumors. It is also increased in adrenogenital syndrome.
11-Deoxycortisol is measured as part of the Metyrapone Test. Metyrapone blocks the formation of cortisol, resulting in increased secretion of ACTH and 11-deoxycortisol in normal individuals. Patients with pituitary or adrenal failure do not increase ACTH secretion or deoxycorticosteroid production after metapyrone administration. An impaired 11-deoxycortisol response confirms the diagnosis of adrenal insufficiency, but does not differentiate primary and secondary causes of adrenal failure.
The test should not be done if plasma cortisol levels are < 3 ug/dL. Estrogen and phenytoin may cause an impaired response to metyrapone.
The reference range is:
08:00 Specimen
16:00 Specimen
0 - 5 ug/dL
0 - 3 ug/dL
Specimen requirement is one green top (heparin) tube of blood.
