17-Hydroxyprogesterone
17-hydroxyprogesterone (17-OHP) is a steroid hormone made by the adrenal glands and gonads. It is a building block in the pathway that produces cortisol.
Screening test for congenital adrenal hyperplasia (21-hydroxylase deficiency). AM specimen, follicular phase preferred. Values >200 ng/dL require ACTH stimulation testing. Newborn screening uses dried blood spot.
Because 17-OHP sits at a key step in cortisol production, its level can reveal blocks in that pathway. It is most often measured to screen for and monitor congenital adrenal hyperplasia, a group of inherited conditions affecting adrenal hormone production. Levels vary with time of day and, in menstruating people, across the cycle.
An elevated 17-OHP can suggest a partial block in cortisol synthesis, as seen in congenital adrenal hyperplasia, but it can also rise temporarily with stress or illness. Mildly high values often prompt a follow-up stimulation test rather than an immediate diagnosis.
A low or normal 17-OHP is generally reassuring against the conditions this test screens for.
17-OHP is interpreted against age-, sex-, and sometimes cycle-specific ranges, and ideally sampled in the morning. Because timing and context strongly affect it, review your result with your clinician.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.