Test Overview

Test Methodology

Gas Chromatography/Mass Spectrometry (GC/MS)

Test Usage

Diagnosis of Smith-Lemli-Opitz syndrome (7-dehydrocholesterol reductase deficiency).

Reference Range*


* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details

Days Test Performed

Varies; test performed once per week

Analytic Time

2 - 8 days

Soft Order Code


MiChart Code

Smith/Lemli/Opitz (7-DHC & 8-DHC)(Sendout)



8-Dehydrocholesterol (8-DHC)
7-Dehydrocholesterol (7-DHC)
SLO (Smith-Lemli-Opitz) Syndrome
Smith-Lemli-Opitz Screen,Plas.

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Laboratory Reference

Mayo SLO (81595)

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Specimen Requirements

Offsite Collection Instructions

Collect specimen in a green top tube from a fasting patient (12 hour fast or just before next feeding for infants). Centrifuge, aliquot serum into a plastic vial within 45 minutes of collection and freeze.

Special Handing

Fasting specimen. Must arrive in lab or aliquot and freeze within 45 minutes.

Normal Volume

0.5 mL plasma

Minimum Volume

0.2 mL plasma

Additional Information

Test sent to Mayo Medical Laboratories.

Billing Information

Fee Codes

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