11-deoxycortisol
The immediate precursor of cortisol — the last step before the body makes its main stress hormone. It is a specialist test used to diagnose a specific form of congenital adrenal hyperplasia (11-beta-hydroxylase deficiency), and in the metyrapone test that assesses the pituitary's reserve.
What it measures
11-deoxycortisol (also called compound S) is the molecule one step before cortisol in the steroid pathway: the enzyme 11-beta-hydroxylase normally converts it into cortisol. Because of this position, it is measured in two specific situations. First, in diagnosing a form of congenital adrenal hyperplasia caused by a deficiency of 11-beta-hydroxylase: when that enzyme is missing, 11-deoxycortisol builds up behind the block while cortisol falls, and the excess precursors are diverted into androgens, so a high 11-deoxycortisol is the tell-tale finding. Second, it is central to the metyrapone test, an older way of assessing the pituitary–adrenal axis: metyrapone deliberately blocks the enzyme, so in a healthy axis the pituitary responds by driving the adrenal glands harder and 11-deoxycortisol rises — a blunted rise indicates the pituitary or adrenal reserve is inadequate. It is a niche endocrine test, always interpreted alongside cortisol, ACTH and other steroid measurements rather than alone.
What a high value can mean
- 11-beta-hydroxylase deficiency — a form of congenital adrenal hyperplasia; the precursor piles up behind the enzyme block.
- A normal metyrapone test response — a healthy rise shows the pituitary–adrenal reserve is intact.
- An adrenal tumour producing steroid precursors — a rarer cause.
What a low value can mean
- A blunted metyrapone test response — points to inadequate pituitary or adrenal reserve (e.g. hypopituitarism, adrenal insufficiency).
- Normal — outside the specific tests it is used for, a low or unremarkable level is expected.
When to discuss with a doctor
11-deoxycortisol is a specialist test used in defined circumstances rather than routinely. It confirms a specific inherited enzyme deficiency (11-beta-hydroxylase) when congenital adrenal hyperplasia is suspected, and it is the measured hormone in the metyrapone test of the pituitary–adrenal axis. In both cases the result only makes sense in context — alongside cortisol, ACTH and the other steroids, and often the response to a stimulation or blocking agent — and is interpreted by an endocrinologist. A high level in the right setting points to the enzyme block; the response in a metyrapone test gauges reserve. Mediora.AI shows 11-deoxycortisol alongside cortisol, ACTH and related precursors so the pattern is read together; the interpretation belongs with your specialist.