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Test Directory Pregnenolone, LC/MS

Pregnenolone, LC/MS

Test Summary

This test may be useful in differentiating among different types of congenital adrenal hyperplasia (CAH). This test may also be used to monitor progress and treatment after diagnosis [1].

CAH is a group of autosomal recessive diseases characterized by deficiencies of enzymes in steroid hormone production. These deficiencies cause imbalances of steroid intermediates and hormones. Clinical manifestations of CAH vary and depend upon the type of defect and severity of the impairment. Therefore, measurement of different steroid hormones can help in diagnosing CAH [1,2].

Pregnenolone is a precursor to all steroid hormones. It can be elevated in some rare types of CAH, including deficiencies of 3-beta-hydroxysteroid dehydrogenase, 17-alpha-hydroxylase, and P450 oxidoreductase. Levels of pregnenolone (and all other steroids) can be low in lipoid adrenal hyperplasia [2].

This test is generally ordered after evaluation of 17-hydroxyprogesterone (test code 17180). 17-hydroxyprogesterone testing, included in newborn screening, is used to detect 21-hydroxylase deficiency (the cause of 95% of CAH). When symptoms and signs suggest CAH, but 21-hydroxylase deficiency and 11-beta-hydroxylase deficiency are ruled out, pregnenolone can be measured to assist in diagnosing other types of CAH [1,2].

Pregnenolone degrades rapidly at refrigerator temperature. Specimens should be frozen immediately after collection and remain frozen until analysis [3].

This test should be interpreted in the context of pertinent clinical and family history as well as physical examination findings.

References
1. Speiser PW, et al. J Clin Endocrinol Metab. 2018;103(11):4043-4088.
2. El-Maouche D, et al. Lancet. 2017;390(10108):2194-2210.
3. Kushnir MM, et al. Clin Chem. 2006;52(8):1559-1567.

Aliases

Specimen Collection

Special Instructions

N/A

Preferred Specimen

0.5 mL serum collected in a red-top tube (no gel)

Minimum Volume

0.2 mL

Instructions

Collect blood in a Vacutainer® with no additives. Allow blood to clot (30 minutes) at room temperature, 18-25° C. Centrifuge and separate the serum from the cells. Freeze as soon as possible.

Patient Preparation

N/A

Storage

N/A

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen -20° C: 14 days
Frozen -70° C: 30 days

Limitations

N/A

Other Acceptable Specimens

N/A

Unacceptable Specimens

Gross hemolysis • Serum separator tube (SST)

Order Code

PRGNEN

EPIC (Premier) Code

LAB3751

Includes

N/A

CPT Code

84140

Billing Code

670433

CPT Statement

Methodology

Chromatography/Mass Spectrometry

FDA Status

This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. The FDA has determined that such clearance or approval is not necessary. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Physician Attestation of Informed Consent

N/A

Testing Laboratory

Quest Diagnostics Nichols Institute
33608 Ortega Highway
San Juan Capistrano CA, 92675

Department

Reference Testing

Reference Range

Adult	22-237 ng/dL
Pediatric
1-59 days	68-1303 ng/dL
60 days-1 year	≤219 ng/dL
2-6 years	≤140 ng/dL
7-9 years	≤156 ng/dL
10-12 years	15-220 ng/dL
13-17 years	12-196 ng/dL

Setup Schedule / Expected Turnaround Time

Evening 6 days a week. Report available 1 - 4 days.