Test Code PREGN Pregnenolone, Serum

Reporting Name

Pregnenolone, S

Useful For

An ancillary test for congenital adrenal hyperplasia, particularly in situations in which a diagnosis of both 21- and 11-hydroxylase deficiency have been ruled out

Confirming a diagnosis of 3-beta-hydroxy dehydrogenase deficiency

Testing Algorithm

For more information see Steroid Pathways.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum

Specimen Required

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1 mL

Collection Instructions:

1. Within 2 hours of collection, serum gel tubes should be centrifuged .

2. Within 2 hours of collection, red-top tubes should be centrifuged, and the serum aliquoted into a plastic vial.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Serum	Frozen	28 days

Special Instructions

Steroid Pathways

Reference Values

CHILDREN/ADOLESCENTS*

Males

0-6 years: Not established

7-9 years: <206 ng/dL

10-12 years: <152 ng/dL

13-15 years: 18-197 ng/dL

16-17 years: 17-228 ng/dL

Tanner Stages

Stage I: <157 ng/dL

Stage II: <144 ng/dL

Stage III: <215 ng/dL

Stage IV-V: 19-201 ng/dL

Females

0-6 years: Not established

7-9 years: <151 ng/dL

10-12 years: 19-220 ng/dL

13-15 years: 22-210 ng/dL

16-17 years: 22-229 ng/dL

Tanner Stages

Stage I: <172 ng/dL

Stage II: 22-229 ng/dL

Stage III: 34-215 ng/dL

Stage IV-V: 26-235 ng/dL

*Kushnir MM, Rockwood AL, Roberts WL, et al. Development and performance evaluation of a tandem mass spectrometry assay for 4 adrenal steroids. Clin Chem. 2006;52(8):1559-1567

ADULTS

≥18 years: 33-248 ng/dL

To convert to nmol/L, multiply the value in ng/dL by 0.03159757.

Day(s) Performed

Monday, Wednesday, Friday

CPT Code Information

84140

LOINC Code Information

Test ID	Test Order Name	Order LOINC Value
PREGN	Pregnenolone, S	2837-3

Result ID	Test Result Name	Result LOINC Value
88645	Pregnenolone, S	2837-3

Interpretation

The diagnosis and differential diagnosis of congenital adrenal hyperplasia (CAH) always require the measurement of several steroids. Patients with CAH due to steroid 21-hydroxylase gene (CYP21A2) variants usually have very high levels of androstenedione, often 5-fold to 10-fold elevations. 17-Hydroxyprogesterone (17-OHPG) levels are usually even higher, while cortisol levels are low or undetectable. All 3 analytes should be tested.

For the HSD3B2 variant, cortisol, 17-OHPG, and progesterone levels will be decreased; 17-hydroxypregnenolone, pregnenolone, and dehydroepiandrosterone (DHEA) levels will be increased.

In the much less common CYP11A1 variant, androstenedione levels are elevated to a similar extent as in CYP21A2 variant, and cortisol is also low, but OHPG is only mildly, if at all, elevated.

In the very rare 17-alpha-hydroxylase deficiency, androstenedione, all other androgen-precursors (17-alpha-hydroxypregnenolone, OHPG, dehydroepiandrosterone sulfate), androgens (testosterone, estrone, estradiol), and cortisol are low, while production of mineral corticoid and its precursors (particularly pregnenolone, 11-dexycorticosterone, corticosterone, and 18-hydroxycorticosterone) are increased.