21-Deoxycortisol
21-Deoxycortisol, also known as 11β,17α-dihydroxyprogesterone or as 11β,17α-dihydroxypregn-4-ene-3,20-dione, is a naturally occurring, endogenous steroid related to cortisol which is formed as a metabolite from 17α-hydroxyprogesterone via 11β-hydroxylase. It is a marker of congenital adrenal hyperplasia due to 21-hydroxylase deficiency. The corticosteroid activity of 21-deoxycortisol is virtually abolished relative to that of cortisol.
As 21-Deoxycortisol can be a high levels in congenital adrenal hyperplasia, and it has structural similarity to cortisol it can cross-react in immunoassays, resulting in a falsely normal or high cortisol result, when the true cortisol is actually low.
