NBS - 17-Hydroxyprogesterone (17-OHP)

The 17-hydroxyprogesterone (17-OHP) test measures blood levels of the steroid precursor 17-hydroxyprogesterone. It screens for and helps diagnose congenital adrenal hyperplasia (CAH) and assesses adrenal or gonadal function in cases of ambiguous genitalia, early puberty, hirsutism, or irregular periods. Samples are usually blood, sometimes with ACTH stimulation for confirmation; elevated levels suggest 21‑hydroxylase deficiency.

Normal 17‑hydroxyprogesterone (17‑OHP) in newborns is typically below about 20–30 ng/mL. Preterm, low‑birth‑weight, or stressed infants often have higher baseline levels, so labs use higher cutoffs; values roughly above 30–40 ng/mL usually prompt further evaluation for congenital adrenal hyperplasia (CAH). Confirm with the testing laboratory or clinician.

Elevated 17‑hydroxyprogesterone suggests impaired cortisol synthesis, most commonly 21‑hydroxylase congenital adrenal hyperplasia. This causes excess androgen production leading to virilization, early puberty, menstrual irregularities, infertility and—in severe forms—salt‑wasting with low blood pressure. Other causes include adrenal or ovarian tumors, stress, or medications. Confirmatory testing (ACTH stimulation, repeat levels, genetic testing) and endocrine referral are recommended.

Normal morning (baseline) 17‑hydroxyprogesterone is usually under about 2 ng/mL (≈6 nmol/L) in adults. Levels vary with sex, menstrual cycle and sampling time. After ACTH stimulation, a normal response stays well below roughly 10 ng/mL (≈30 nmol/L); higher stimulated values suggest congenital adrenal hyperplasia. Always compare with the laboratory’s reference range and clinical context.

17‑hydroxyprogesterone (17‑OHP) is usually normal in PCOS. Mild or borderline elevations can occur, often reflecting an adrenal contribution, but clearly raised or persistent 17‑OHP suggests nonclassic congenital adrenal hyperplasia (NCAH) and requires further evaluation. Early‑follicular measurement and an ACTH stimulation test clarify diagnosis; interpret results with an endocrinologist or clinician.

17α‑hydroxylase deficiency (a form of congenital adrenal hyperplasia) causes cortisol and sex‑steroid deficiency with excess mineralocorticoids. Common symptoms: high blood pressure and low potassium; delayed or absent puberty and lack of secondary sexual characteristics, including scant pubic/axillary hair; primary amenorrhea in 46,XX individuals; undervirilization or ambiguous genitalia and undescended testes in 46,XY individuals; plus fatigue.