17-Hydroxypregnenolone, Mass Spectrometry (Endocrine Sciences)

TEST: 140715
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CPT: 84143
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Expected Turnaround Time

5 - 10 days

Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.

Related Information

Specimen Requirements

Specimen

Serum or plasma. frozen

Volume

1 mL

Minimum Volume

0.3 mL adult; 0.1 mL pediatric (Note: This volume does not allow for repeat testing.)

Container

Red-top tube, gel-barrier tube, or lavender-top (EDTA) tube

Collection

Transfer the serum or plasma into a LabCorp PP transpak frozen purple tube with screw cap (LabCorp N° 49482) and freeze. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Freeze.

Stability Requirements

Temperature

Period

Room temperature

6 hours

Refrigerated

1 day

Frozen

2 years

Causes for Rejection

Nonserum or non-EDTA plasma specimen received

Test Details

Methodology

High-pressure liquid chromatography/tandem mass spectrometry (LC/MS-MS)

Reference Interval

• Premature (26 to 28 weeks): day 4: 375−3559 ng/dL

• Premature (31 to 35 weeks): day 4: 64−2380 ng/dL

• 3 days: 10−829 ng/dL

• 1 to 5 months: 36−763 ng/dL

• 6 to 11 months: 42−540 ng/dL

• 12 to 23 months: 14−207 ng/dL

• 24 months to 5 years: 10−103 ng/dL

• 6 to 9 years: 10−186 ng/dL

• Pubertal: 44−235 ng/dL

• Adults: 53−357 ng/dL

Additional Information

In humans, the adrenal glands and the gonads produce steroid hormones.1,2 The formation of pregnenolone from cholesterol is the first step in steroidogenesis. Steroidogenesis continues along two paths from pregnenolone. 17-Hydroxypregnenolone is produced from pregnenolone through the enzymatic action of 17-α-hydroxylase (17α-H). 3-β-hydroxysteroid dehydrogenase (3β-HSD) mediates the conversion of 17-hydroxypregnenolone to 17-hydroxyprogesterone. Alternatively, the enzyme 17,20 lyase can convert 17-hydroxypregnenolone to dehydroepiandrosterone (DHEA). 17α-H and 17,20 lyase activity are both mediated by a single microsomal cytochrome P450 complex.

17-hydroxypregnenelone levels have been shown to remain in the normal range in patients with Cushing.3 Levels can be suppressed with dexamethasone inhibition and increased with exogenous ACTH stimulation.3 Levels during the follicular phase of the menstrual cycle tend to be higher than during the luteal phase.3 17-hydroxypregnenelone levels have been shown to be elevated in patients with idiopathic hirsutism.4

Footnotes

1. Demers LM, Whitley R. Function of the adrenal cortex. In: Burtis CA, Ashwood ER, eds. Tietz Textbook of Clinical Chemistry. 3rd ed. Philadelphia, Pa: WB Saunders Co;1999:1530-1569.
2. Donohoue PA, Parker K, Migeon CJ. Congenital adrenal hyperplasia. In Scriver CR, Beaudet AL, Sly WS, et al, eds. The Metabolic and Molecular Bases of Inherited Disease. 1995; 2929-2966.
3. McKenna TJ, Brown RD. Pregnenolone in man: Plasma levels in states of normal and abnormal steroidogenesis. J Clin Endocrinol Metab. 1974 Mar; 38(3):480-485. 4360922
4. McKenna TJ, Miller RB, Liddle GW. Plasma pregnenolone and 17-OH-pregnenolone in patients with adrenal tumors, ACTH excess, or idiopathic hirsutism. J Clin Endocrinol Metab. 1977 Feb; 44(2):231-236.190251

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
140715 17-Hydroxypregnenolone, MS 6765-2 140725 17 OH Pregnenolone, Serum, MS ng/dL 6765-2