AT A GLANCE
- 17-OH progesterone (17-OHP) is produced by the adrenal glands and ovaries; it is an intermediate in the cortisol synthesis pathway
- Normal range in females depends on menstrual cycle phase — follicular phase (days 1–12): ~15–70 ng/dL (0.5–2.1 nmol/L); luteal phase (days 13–28): ~35–290 ng/dL (1.0–8.7 nmol/L)
- A result that looks elevated may be normal if collected in the luteal phase — always check which phase-specific range applies to your result
- Low 17-OHP in the early follicular phase is physiologically normal and rarely clinically significant
- 17-OHP is not the same as progesterone — they are different hormones; the tests are not interchangeable
- LC/MS-MS is a more specific test method than immunoassay; reference ranges differ between methods — do not compare results across methods
- High 17-OHP with androgen-excess symptoms most commonly indicates non-classic CAH or PCOS
- Normal ranges vary by lab, age, sex, and test method. Results can also vary significantly depending on time of day, cycle phase, medications, and assay method. Always use the reference range on your specific lab report.
NORMAL 17-OH PROGESTERONE LEVELS IN FEMALES
| Population | ng/dL | nmol/L | Notes |
|---|---|---|---|
| Adult females — follicular (days 1–12) | 15–70 | 0.5–2.1 | Best phase for baseline testing |
| Adult females — luteal (days 13–28) | 35–290 | 1.0–8.7 | Physiologically elevated; not abnormal |
| Adult females — postmenopausal | < 51–70 | < 1.5–2.1 | Lab-dependent |
| Adult males | < 220 | < 6.6 | Less phase-dependent |
| Prepubertal children | < 100 | < 3.0 | Method-dependent |
| Newborns, first 24 hrs | ~1,000–3,000 | ~30–90 | Falls rapidly; basis for CAH screen |
| Newborns, >24–72 hrs | < 100–200 | < 3–6 | Lab-specific cutoffs |
Unit conversions:
- ng/dL → nmol/L: multiply by 0.0303
- nmol/L → ng/dL: multiply by 33.0
- ng/dL → ng/mL: divide by 100 (so 70 ng/dL = 0.70 ng/mL)
All ranges are illustrative. Reference intervals differ between laboratories and assay methods. Always use the range printed on your lab report.
If your result says "< 50 ng/dL" or "< 20 ng/dL": This is a reporting threshold, not a dangerously low value. For women in the follicular phase, a result below 50 ng/dL is within or below the normal range — a reassuring finding, not a cause for concern.
If your result appears "high" but your blood was drawn after ovulation (luteal phase): A luteal-phase result of up to 290 ng/dL is entirely normal. A result that looks elevated may simply reflect the expected post-ovulation rise. Always confirm which cycle phase applies to your reference range before drawing conclusions.
WHAT LEVEL OF 17-OHP IS CONCERNING?
| Result (ng/dL) | Typical interpretation |
|---|---|
| < 50, early follicular phase | Normal — reporting threshold, not a low value |
| 15–70, follicular phase | Normal follicular range |
| 35–290, luteal phase | Normal luteal range — not elevated |
| > 70 follicular / > 290 luteal | Above phase-specific range — recheck cycle phase; repeat if needed |
| 200–1,000, follicular phase | Mildly-moderately elevated — consider ACTH stimulation test to evaluate for non-classic CAH |
| > 1,000, adults | Significant elevation — warrants endocrinology evaluation |
| > 2,000, newborns/infants | Strong concern for classic CAH — requires prompt clinical evaluation |
Thresholds are illustrative — always use the reference range on your specific lab report and interpret alongside clinical context.
17-OH PROGESTERONE LEVELS BY MENSTRUAL CYCLE PHASE
17-OHP follows the ovarian cycle in premenopausal women. The corpus luteum — the temporary structure that forms after ovulation — produces 17-OHP alongside progesterone, causing levels to rise through the luteal phase. This is normal and expected.
Why this matters for your result: A result of 200 ng/dL collected on day 21 of your cycle (luteal phase) is within the upper normal range. The same value collected on day 3 (early follicular phase) is above the follicular-phase upper limit and warrants clinical evaluation. Both are the same number — the interpretation changes entirely based on cycle day.
Best collection conditions for an interpretable baseline:
- Days 2–5 of the menstrual cycle (early follicular phase)
- Early morning (8–10 AM) — adrenal hormones are at daily peak
- Before starting steroid medications or hormonal contraceptives if clinically feasible
IS 17-OH PROGESTERONE THE SAME AS PROGESTERONE?
No. They are structurally related but functionally different hormones, and the tests are not interchangeable.
| Progesterone | 17-OH Progesterone (17-OHP) | |
|---|---|---|
| Primary source | Ovaries (corpus luteum) | Adrenal glands + ovaries |
| Main function | Prepares uterine lining; supports pregnancy | Intermediate in cortisol synthesis |
| Rises in luteal phase | Yes | Yes |
| Tested for | Ovarian function, pregnancy | CAH, androgen excess, adrenal function |
| High result indicates | Ovulatory issues, luteal phase problems | CAH, enzyme defect, androgen excess |
If your lab report says "Progesterone" and you were expecting "17-OH Progesterone" — or vice versa — those are different tests. Check the full test name on your report before comparing results or reference ranges.
LOW 17-OH PROGESTERONE IN FEMALES
Low 17-OHP in females is among the most common search-driven concerns for this biomarker — and it is usually normal.
What is considered low? Below the lower end of the follicular-phase reference range for your lab — often below 15 ng/dL (0.5 nmol/L), though lab-specific floors vary. Many labs report low results as "< 50 ng/dL," "< 20 ng/dL," or a similar threshold.
What does "17-hydroxyprogesterone less than 50" mean? A result reported as "< 50 ng/dL" means the measured level is below 50 ng/dL — the detection floor or reporting threshold of the assay. It does not mean the level is zero or that something is wrong. For adult women in the follicular phase, the reference range typically begins at 15–20 ng/dL, so a result below 50 is normal. There is no clinical action required for this result in isolation.
Common reasons for low or low-normal 17-OHP in females:
- Early follicular phase (days 1–5) — physiologically lowest point in the cycle; normal
- Combined hormonal contraceptives — suppress ovarian and adrenal androgen production; low 17-OHP is expected
- Glucocorticoid therapy — hydrocortisone, prednisone, dexamethasone all suppress ACTH and lower 17-OHP; this is the treatment goal in managed CAH
- Postmenopause — ovarian 17-OHP production declines; lower values are expected
- Normal variation — many women have low-normal levels throughout the cycle without any underlying condition
When is low 17-OHP clinically relevant? Only in the context of suspected adrenal insufficiency — and even then, cortisol and ACTH are the more appropriate primary markers. Fatigue, low blood pressure, salt craving, and weight loss alongside a low 17-OHP should prompt cortisol/ACTH evaluation.
WHAT IS 17-OH PROGESTERONE?
17-OHP (17-hydroxyprogesterone, 17α-hydroxyprogesterone) is produced primarily by the adrenal glands and, in premenopausal women, also by the ovaries. It sits in the middle of the cortisol synthesis pathway — made from progesterone, converted by the enzyme 21-hydroxylase into 11-deoxycortisol, then into cortisol.
When blocked: If 21-hydroxylase is deficient (the cause of congenital adrenal hyperplasia), 17-OHP cannot be efficiently converted. It accumulates. The pituitary releases more ACTH, driving further 17-OHP buildup and diversion of excess precursors into androgens — explaining the androgen-excess symptoms that accompany CAH.
HIGH 17-OH PROGESTERONE IN FEMALES
Most common causes:
- Non-classic CAH (21-hydroxylase deficiency) — the most important cause of persistent adult-onset elevation. Baseline 17-OHP typically 200–1,000+ ng/dL; confirmed by ACTH stimulation (stimulated value above ~1,500 ng/dL)
- PCOS — may cause mild elevation from increased ovarian androgen production; typically produces only mild ACTH-stimulated increases compared with non-classic CAH
- Luteal-phase collection — result interpreted against follicular-phase range; not a pathological elevation
- Classic CAH in an undiagnosed older child or adult — markedly elevated, usually with significant androgen-excess symptoms
- Adrenal tumour — rare; usually accompanied by additional signs of adrenal hypersecretion
Symptoms associated with high 17-OHP / androgen excess:
- Hirsutism (excess body or facial hair)
- Acne, particularly jaw and back acne
- Irregular or absent periods
- Infertility
- Early pubic or underarm hair in children (precocious adrenarche)
- Rapid growth with early bone maturation in childhood
- In female newborns with classic CAH: virilisation of external genitalia at birth
When to investigate further: Persistent elevation in the early follicular phase (above 200 ng/dL) alongside any of the above symptoms warrants an ACTH stimulation test to evaluate for non-classic CAH.
When is high 17-OHP an emergency?
In adults, even marked elevations above 1,000 ng/dL are clinically significant but not typically acute emergencies — they warrant endocrinology evaluation within days to weeks, not hours. In newborns, high 17-OHP indicating classic CAH with salt-wasting is a genuine emergency requiring prompt treatment to prevent a life-threatening electrolyte crisis. An adult with known CAH who develops acute symptoms (severe weakness, vomiting, low blood pressure, confusion) requires emergency evaluation regardless of 17-OHP level.
17-OH PROGESTERONE LC/MS-MS NORMAL RANGE IN FEMALES — AND WHY METHOD MATTERS
Many lab reports include "LCMS" or "LC/MS-MS" in the test name — this refers to liquid chromatography–tandem mass spectrometry.
Why it matters for 17-OHP: Immunoassay can cross-react with structurally similar steroids, producing falsely elevated 17-OHP — especially in newborns and borderline adult cases. LC/MS-MS separates 17-OHP from similar compounds before measuring it, giving a more specific result.
Practical effect: LC/MS-MS reference ranges are generally lower than immunoassay ranges. A borderline elevated immunoassay result may be normal by LC/MS-MS. Do not compare a result from one method against a reference range from the other.
LabCorp test 500540 is their LC/MS-MS method for 17-hydroxyprogesterone. If your report says "17-OH Progesterone LCMS" or includes "LC/MS-MS" in the test name, the reference ranges on that report are specific to that method.
CONGENITAL ADRENAL HYPERPLASIA (CAH)
CAH is a group of inherited adrenal enzyme defects; over 90% are caused by 21-hydroxylase deficiency. 17-OHP is the primary diagnostic marker.
Classic CAH (severe): Presents in infancy. 17-OHP markedly elevated (often above 2,000–10,000 ng/dL or higher). The salt-wasting form causes dangerous electrolyte imbalance; newborn screening exists to catch this early and prevent life-threatening crises.
Non-classic CAH (mild): Presents in childhood, adolescence, or adulthood with androgen-excess symptoms. Baseline 17-OHP typically 200–1,000 ng/dL; confirmed by ACTH stimulation. Often misdiagnosed as PCOS. Manageable with low-dose glucocorticoids when treatment is indicated.
Newborn screening: Most countries screen for 17-OHP at birth. Premature or sick newborns often have false-positive screens. Confirmatory serum testing is required before a diagnosis is made.
WHEN IS 17-OHP TESTED?
Common clinical reasons for ordering 17-OHP:
- Irregular or absent periods
- Hirsutism, acne, or signs of androgen excess
- Infertility evaluation
- Suspected PCOS — to exclude non-classic CAH
- Precocious puberty in children
- Newborn with ambiguous genitalia or abnormal newborn screen
- Monitoring treatment in known CAH
- Evaluation of adrenal function
COMMON PHRASES SEEN ON LAB REPORTS
17-OH PROGESTERONE
17-OHP
17-HYDROXYPROGESTERONE
17-HYDROXYPROGESTERONE, LC/MS-MS
17-OH PROGESTERONE LCMS
17-OH PROGESTERONE, SERUM
17-HYDROXYPROGESTERONE (F) / (L) [F=follicular, L=luteal]
17-OHP HIGH / WARNINGHIGH 17-OHP
17-HYDROXYPROGESTERONE, IMMUNOASSAY
17α-HYDROXYPROGESTERONE
PROGESTERON 17-OH / 17-OH-PROGESTERON (German)
17-HYDROXYPROGESTÉRONE (French)
17-HYDROXYPROGESTERONA (Spanish/Portuguese)
17-IDROSSIPROGESTERONE (Italian)
17-HYDROKSYPROGESTERON (Polish)
17-OH Progesterone
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Frequently Asked Questions
What is a normal 17-OH progesterone level for females?
What does low 17-hydroxyprogesterone in females mean?
What does 17-hydroxyprogesterone less than 50 mean?
Is 17-OH progesterone the same as progesterone?
What is the normal range for 17-OH progesterone in ng/mL and nmol/L?
What does high 17-OH progesterone mean in females?
What is the 17-OH progesterone LCMS normal range female?
What does elevated 17-OHP mean for PCOS?
What does a high 17-OHP in a newborn mean?
What is an ACTH stimulation test for 17-OHP?
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Why would 17-OH progesterone be low during the follicular phase?
All our content is backed by peer-reviewed studies, academic research, and trusted medical sources. We’re committed to accuracy and transparency — see our editorial policy for details.
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Congenital Adrenal Hyperplasia Due to Steroid 21-Hydroxylase Deficiency: An Endocrine Society Clinical Practice Guideline
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Nonclassic congenital adrenal hyperplasia due to 21-hydroxylase deficiency: clinical presentation, diagnosis, treatment, and outcome
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17-OH Progesterone, LC/MS