17-Alpha Hydroxy Progesterone

Function

17-hydroxyprogesterone (17-OHP) is a precursor hormone in the synthesis of cortisol. The enzyme 21-hydroxylase is required to convert 17-OHP into the next stage of cortisol production. If this enzyme is deficient, 17-OHP builds up in the blood. This pathway is critical for the adrenal glands' ability to produce life-sustaining steroid hormones.

Why it is Ordered

This test is primarily used to screen for and diagnose Congenital Adrenal Hyperplasia (CAH). While newborns are routinely screened, the test is also used in adults to detect 'Late-Onset' (Non-classic) CAH, which can cause symptoms later in life such as hirsutism (excess hair growth), irregular periods, and infertility in women, or early puberty in children. It is also used to rule out adrenal tumors.

Associated Conditions

• Congenital Adrenal Hyperplasia (CAH): Specifically the 21-hydroxylase deficiency type.
• Polycystic Ovary Syndrome (PCOS): 17-OHP is often tested to differentiate PCOS from non-classic CAH, as symptoms overlap.
• Adrenal Tumors: Some tumors may secrete high levels of hormone precursors.
• Hirsutism and Virilization: Excess 17-OHP is shunted into androgen production, causing male-pattern hair growth in females.