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Pregnenolone, LC/MS
Test CodePREGNE
Quest Code
31493
CPT Codes
84140
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°C to 25° C. Centrifuge and separate the serum from the cells. Freeze as soon as possible.
Transport Temperature
Frozen
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen -20° C: 14 days
Frozen -70° C: 30 days
Refrigerated: 72 hours
Frozen -20° C: 14 days
Frozen -70° C: 30 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Gross hemolysis • Serum separator tube (SST)
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. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Monday-Friday, Sunday Morning Report available: 2 Days
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 |
Clinical Significance
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.
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.
Performing Laboratory
| Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
| 33608 Ortega Highway |
| San Juan Capistrano, CA 92675-2042 |
