Definition
- 17α-Hydroxyprogesterone, also known as hydroxyprogesterone, is a 21-carbon steroid produced in the adrenals " and also in the ovaries, testes, and placenta " that serves as a biosynthetic precursor to cortisol.
- Normal range: 18 " 469 ng/dL (see Table 16.1).
TABLE 16 " 1Range of Normal Values for 17a-HydroxyprogesteroneView LargeTABLE 16 " 1Range of Normal Values for 17a-Hydroxyprogesterone Patient Group Median (ng/dL) Range (ng/dL) Male (20 " 59 y) 143 60 " 342 Female Follicular phase 67 19 " 182 Luteal phase 210 22 " 469 Taking oral contraceptives 79 18 " 251 Postmenopausal 46 20 " 172
Use
- Diagnosis and management of congenital adrenal hyperplasia, hirsutism, and infertility
Interpretation
Increased In
- The luteal phase of menstruating women and pregnancy, during which it rises.
- When defective 21-alpha hydroxylase and 11-beta hydroxylase are present.
- The most common form of CAH, where deficiency of the enzyme 21-hydroxylase blocks normal synthesis of cortisol, leading to a compensatory increase of ACTH secretion; this results in increased levels.
Limitations
- Circulating normally exhibits a diurnal pattern similar to that of cortisol, with higher values in the early morning than in the late afternoon. Hence, the time of collection should be standardized.
- Spuriously elevated levels are sometimes seen in premature and sick newborns due to interference with other steroid metabolites. 17α-Hydroxypregnenolone sulfate (percent cross-reactivity: 3.8%) has been identified as the most significant interferent in direct assays.
- 17α-Hydroxyprogesterone values for women with late-onset CAH have been found to overlap with those encountered in hirsute, oligomenorrheic women who do not have the disorder. Accordingly, it is important to determine ACTH-stimulated 17α-hydroxyprogesterone levels in women suspected of having late-onset CAH.