7 - 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.
Serum (preferred) or plasma, frozen
1.1 mL (Note: This volume does not allow for repeat testing.)
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, or green-top (heparin) tube
Serum or plasma must be separated from cells and transferred to a plastic transport tube within one hour of collection. The specimen should be frozen immediately and maintained frozen until tested. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Liquid chromatography/tandem mass spectrometry (LC/MS-MS)
In humans, steroid hormones are produced by the adrenal glands and the gonads.1,2 The formation of pregnenolone from cholesterol is the first step in steroidogenesis and is mediated by the proteolytic enzyme, single cholesterol side-chain cleavage enzyme (P450 scc). Steroidogenesis continues along two paths from pregnenolone. 17-Hydroxypregnenolone is produced from pregnenolone through the enzymatic action of 17α-hydroxylase (17α-H). Alternatively, pregnenolone is converted to progesterone through the enzymatic action of 3β-hydroxysteroid dehydrogenase (3β-HSD).
Pregnenolone levels have been shown to remain in the normal range in patients with Cushing syndrome and hyperaldosteronism.3,4 Levels can be suppressed with dexamethasone inhibition and increased with exogenous ACTH stimulation.3 Pregnenolone levels have been shown to be elevated in patients with idiopathic hirsutism.4
Since the various forms of congenital adrenal hyperplasia (CAH) result from enzymatic defects in the adrenal steroidogenic pathways, measurement of pregnenolone levels can be useful in diagnosis. Pregnenolone levels tend to be elevated in several forms of CAH, particularly in 17α-H deficiency and 3β-HSD deficiency since these enzymes catalyze steps immediately after pregnenolone in the steroidogenic pathways.2
|Order Code||Order Code Name||Order Loinc||Result Code||Result Code Name||UofM||Result LOINC|
|140707||Pregnenolone, MS||140709||Pregnenolone, MS||ng/dL||2837-3|
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