Sign in →

Test Code 17OHP 17-Hydroxypregnenolone, Serum

Reporting Name

17-Hydroxypregnenolone, S

Useful For

As an ancillary test for congenital adrenal hyperplasia (CAH), particularly in situations in which a diagnosis of both 21- and 11-hydroxylase deficiency have been ruled out

 

Confirming a diagnosis of 3-beta-hydroxysteroid dehydrogenase deficiency

 

As part of a battery of tests to evaluate women with hirsutism or infertility; both can result from adult-onset CAH

Testing Algorithm

For information see Steroid Pathways.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 28 days
  Refrigerated  28 days

Special Instructions

Day(s) Performed

Monday, Wednesday, Friday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

84143

LOINC Code Information

Test ID Test Order Name Order LOINC Value
17OHP 17-Hydroxypregnenolone, S 6765-2

 

Result ID Test Result Name Result LOINC Value
81151 17-Hydroxypregnenolone, S 6765-2

Clinical Information

Congenital adrenal hyperplasia (CAH) is caused by inherited defects in steroid biosynthesis. Deficiencies in several enzymes can cause CAH, including 21-hydroxylase (CYP21A2 variants; 90% of cases), 11-hydroxylase (CYP11A1 variants; 5%-8%), 3-beta-hydroxysteroid dehydrogenase (3-beta-HSD) (HSD3B2 variants; <5%), and 17-alpha-hydroxylase (CYP17A1 variants; 125 cases reported to date). The resulting hormone imbalances (reduced glucocorticoids and mineralocorticoids; elevated steroid intermediates and androgens) can lead to life-threatening, salt-wasting crises in the newborn period and incorrect gender assignment of virilized females.

 

The adrenal glands, ovaries, testes, and placenta produce steroid intermediates, which are hydroxylated at the position 21 (by 21-hydroxylase) and position 11 (by 11-hydroxylase) to produce cortisol. Deficiency of either 21-hydroxylase or 11-hydroxylase results in decreased cortisol synthesis and loss of feedback inhibition of adrenocorticotropic hormone (ACTH) secretion. The consequent increased pituitary release of ACTH drives increased production of steroid intermediates.

 

The steroid intermediates are oxidized at position 3 by 3-beta-HSD. The 3-beta-HSD enzyme allows formation of 17-hydroxyprogesterone (17-OHPG) from 17-hydroxypregnenolone and progesterone from pregnenolone. When 3-beta-HSD is deficient, cortisol is decreased, 17-hydroxypregnenolone and pregnenolone levels may increase, and 17-OHPG and progesterone levels are low. Dehydroepiandrosterone is also converted to androstenedione by 3-beta-HSD and may be elevated in patients affected with 3-beta-HSD deficiency.

 

The best screening test for CAH, most often caused by either 21- or 11-hydroxylase deficiency, is the analysis of 17-OHPG, along with cortisol and androstenedione. CAH21 / Congenital Adrenal Hyperplasia (CAH) Profile for 21-Hydroxylase Deficiency, Serum allows the simultaneous determination of these 3 analytes. Alternatively, these tests may be ordered individually: OHPG / 17-Hydroxyprogesterone, Serum; CINP / Cortisol, Mass Spectrometry, Serum; and ANST / Androstenedione, Serum.

 

If both 21- and 11-hydroxylase deficiency have been ruled out, analysis of 17-hydroxypregnenolone and pregnenolone may be used to confirm the diagnosis of 3-beta-HSD or 17-alpha-hydroxylase deficiency.

 

For more information see Steroid Pathways.

Cautions

At birth, the hypothalamic-pituitary-adrenal axis and the hypothalamic-pituitary gonadal axis are activated, and adrenal and sex steroid levels are high. In preterm infants, the elevations can be even more pronounced due to illness and stress. As a result, preterm infants may occasionally have 17-hydroxypregnenolone levels up to 9799 ng/dL. Term infants (0-28 days) will have levels below 3104 ng/dL. These then decrease over the following 2 years to prepubertal levels (<277 ng/dL).

Report Available

3 to 7 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)