Pregnenolone LCMS
- Laboratory
- Quest Diagnostics
- Test code
- 31493
- Specimen
- Serum
- Fasting
- Not stated as required
What the laboratory says this test is for
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.References1. 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.
Quest Diagnostics test directory, test code 31493