11-deoxycorticosterone measurement by solid phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
11-deoxycorticosterone (DOC) is a steroid synthetic pathway intermediate in the production of aldosterone, the main mineralocorticoid regulating sodium and water balance at the level of the kidney and therefore, blood pressure. DOC is only a weak mineralocorticoid in healthy individuals, as it possesses only around 1/20th the activity of aldosterone. However, DOC accumulates to pathologically significant concentrations in specific forms of CAH (11β-hydroxylase or 17α-hydroxylase deficiencies), resulting in mineralocorticoid hypertension in the context of low renin and aldosterone measurements. DOC measurement is therefore a useful additional tool in the diagnosis and monitoring of CAH forms associated with mineralocorticoid hypertension. DOC can also occasionally be produced by adrenal tumours, resulting in mineralocorticoid hypertension, despite suppressed renin and aldosterone values. Finally, measurement of DOC is also useful in the monitoring of patients taking drugs which inhibit 11β-hydroxylase. Examples of these include Cushing’s patients being treated with metyrapone, as well as those taking azole antifungals (particularly pozaconazole), all of whom are susceptible to mineralocorticoid hypertension secondary to increased DOC concentrations.