What this marker measures
Baseline 17-OH progesterone is most informative when drawn in the morning during the follicular phase. ACTH stimulation testing is used to confirm CAH when the baseline is borderline.
High or low: what it can mean
High 17-OH Progesterone
Marked elevation — particularly after an ACTH stimulation test — supports a diagnosis of congenital adrenal hyperplasia, most often from 21-hydroxylase deficiency. Mild elevations can occur with PCOS or non-classic CAH.
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Low 17-OH Progesterone
Low values are normal and do not by themselves indicate disease. In the follicular phase or after menopause, values are physiologically low.
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Frequently asked questions
What is 17-OH Progesterone?
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17-OH progesterone is an intermediate in adrenal steroid biosynthesis. It is mainly used to screen for and monitor congenital adrenal hyperplasia (CAH).
What does 17-OH Progesterone measure?
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Baseline 17-OH progesterone is most informative when drawn in the morning during the follicular phase. ACTH stimulation testing is used to confirm CAH when the baseline is borderline.
What does high 17-OH Progesterone mean?
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Marked elevation — particularly after an ACTH stimulation test — supports a diagnosis of congenital adrenal hyperplasia, most often from 21-hydroxylase deficiency. Mild elevations can occur with PCOS or non-classic CAH.
What does low 17-OH Progesterone mean?
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Low values are normal and do not by themselves indicate disease. In the follicular phase or after menopause, values are physiologically low.
Related biomarkers
Editorial note
LabTestly explains lab markers using plain-English educational content. Reference ranges may vary by laboratory and should be interpreted with a clinician.
Educational content · Editorially reviewed for clarity · Last updated
Common sources used for lab-test education
Not medical advice
This page is for general understanding only and does not replace medical advice from your clinician. Reference ranges can vary by laboratory, age, sex, pregnancy status, medications, and clinical context.