17-Hydroxyprogesterone
Overview
17-Hydroxyprogesterone is a steroid intermediate in the production of cortisol and androgens by the adrenal cortex and gonads. It serves as a marker of adrenal steroidogenesis, particularly 21-hydroxylase activity in the cortisol synthesis pathway. Elevated levels indicate congenital adrenal hyperplasia (most commonly 21-hydroxylase deficiency), while low levels suggest adrenal insufficiency or 17-alpha-hydroxylase deficiency. Clinically, 17-hydroxyprogesterone measurement is essential for newborn screening, diagnosis of CAH, and monitoring glucocorticoid replacement therapy.
Clinical Use Cases
- Newborn screening for congenital adrenal hyperplasia (CAH).
- Diagnosis of 21-hydroxylase deficiency CAH.
- Monitoring treatment compliance and dosing in CAH patients.
- Evaluation of non-classic CAH in females with hirsutism or infertility.
- Assessment of adrenal function in ambiguous genitalia.
Specimen Types
- Serum.
- Plasma (EDTA).
- Dried blood spot (newborn screening).
- Amniotic fluid (prenatal diagnosis).
Measurement Methods
- Immunoassay (chemiluminescent, ELISA).
- Liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- Radioimmunoassay.
Test Preparation and Influencing Factors
- Morning sample preferred due to diurnal rhythm.
- ACTH stimulation test enhances diagnostic sensitivity for non-classic CAH.
- Pregnancy elevates levels (progesterone interference).
- Oral contraceptives and menstrual cycle phase affect baseline.
- Stress or illness increases ACTH-driven production.
- Assay cross-reactivity with other steroids possible.
Synonyms
- 17-OHP.
- 17-Hydroxypregnanolone.