What does the 17-Hydroxyprogesterone test measure?

Why is 17-Hydroxyprogesterone measured?

Measurement of 17-OHP is the biochemical cornerstone of screening and diagnosing congenital adrenal hyperplasia due to 21-hydroxylase deficiency, which accounts for over 90% of CAH cases. Markedly elevated basal values confirm classic CAH in symptomatic neonates or children; moderate elevations prompt an ACTH stimulation test to detect non-classic forms that present with signs of androgen excess in adolescence or adulthood. The test is also included in newborn screening programmes in many jurisdictions, where a very high value triggers confirmatory testing.

Reference ranges

Standard reference

Luteal phase adult women approximately 50–250 ng/dL; follicular phase <80 ng/dL; post-menopause <51 ng/dL; males <220 ng/dL. Neonatal values are markedly higher and decline over the first week of life.

Functional medicine optimal

There is no single 'optimal' value; interpretation hinges on age, sex, menstrual phase, and the clinical question. In adult women being evaluated for hyperandrogenism, a basal 17-OHP below approximately 200 ng/dL makes non-classic CAH unlikely, while values above 1000 ng/dL are highly suggestive and those in between warrant a cosyntropin stimulation test.

Units

ng/dL, nmol/L

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.