DHEA‑S is a steroid hormone which is produced from the precursor cholesterol in the zona reticularis and broad fascia of the adrenal cortex. The determination of elevated DHEA‑S values is an important aid in the diagnosis of hirsutism and virilism. In addition to a differential diagnosis of hirsutism and virilism further indications for this parameter are all forms of androgenisation, hyperprolactinemia, polycystic ovarian syndrome, and the exclusion of an androgen producing tumor of the adrenal cortex. DHEA‑S exhibits only a weak androgenic activity but can be metabolized to more active androgens such as androstendione and testosterone, which can indirectly cause hirsutism and virilism.
From 7 years of age onwards, an increase in DHEA‑S levels is observed which then gradually after the age of 30 begins to fall again. Only elevated DHEA‑S concentrations are of clinical importance; other factors which can be responsible for DHEA‑S excess production are genetic enzyme defects of the adrenal cortex (adrenogenital syndrome), hyperplasia of the adrenal cortex as well as androgen producing tumors.
The rate of secretion of DHEA‑S into the blood stream is only slightly more than the rate observed for DHEA. As a consequence of the DHEA‑S half‑life of approximately 1 day, the DHEA‑S level is however about a thousand fold greater. DHEA‑S is relatively strongly bound to albumin, only a small portion is non - protein bound, and none appears to be bound to sex hormone‑binding globulin (SHBG). Due to its high concentration and low inter - and intra‑day variability, DHEA‑S is an excellent indicator of adrenal cortex androgen production.
Together with testosterone, DHEA‑S assays represent the assay of choice for initial screening tests to determine whether androgen values are elevated in hirsutism. Approximately 84 % of the women suffering from hirsutism exhibit elevated androgen levels. The main purpose of this is to exclude the presence of androgen producing tumors (from the adrenal cortex or the ovaries). Tumor relevant values in women are those values exceeding 700 μg/dL DHEA‑S.