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Test Code Epic LAB1073 Pregnenolone, Serum

Additional Codes

SQ code PREGNOM

Mayo code PREGN

Reporting Name

Pregnenolone, S

Specimen Type

Serum

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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.


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

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

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

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

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Method Description

Deuterium-labeled internal standards (pregnenolone-d4 and 17-hydroxypregnenolone-d3) are added to each sample. Pregnenolone and the internal standards are extracted from the sample using solid phase extraction. The extracts are washed, dried under nitrogen, derivatized using hydroxylamine, and analyzed by liquid chromatography tandem mass spectrometry. The mass spectrometer has an electrospray interface and is operated in the multiple-reaction monitoring positive mode. A 7-point standard curve is extracted and derivatized with each batch of samples.(Unpublished Mayo method)

Report Available

3 to 7 days