Smith-Lemli-Opitz Screen

Last Modified: 6/30/2022 9:56:34 AM


Medical Necessity Documentation:  
Client Notes:  
Patient Preparation: Fasting (12 hours or more, infants just before next feeding)
Specimen Requirements:

0.5  mL Frozen Plasma from a Green Top Tube - Na Heparin in a Plastic Vial
Collection Instructions: Centrifuge specimen and aliquot plasma within 45 minutes of drw. Send plasma frozen.
Minimum Volume: 0.2 mL Plasma
Transport & Storage: Temperature/Stability:

14 days Ambient (Transport)
28 days Refrigerated 
92 days Frozen
Reference Range:
7-Dehydrocholesterol ≤2.0 mg/L
8-Dehydrocholesterol ≤0.3 mg/L
Critical Ranges:  
Test Comments: Quantitative results are provided when positive.

Interpretation: Elevated plasma concentrations of 7-dehydrocholesterol (7-DHC) and 8-dehydrocholesterol (8-DHC) are highly suggestive of a biochemical diagnosis of Smith-Lemli-Opitz (SLO).
Mild elevations of these cholesterol precursors can be detected in patients with hypercholesterolemia and patients treated with haloperidol. However, the 7-DHC to cholesterol ratio is only elevated in SLO patients.
Methodology: Gas Chromatography Mass Spectrometry (GCMS)
Clinical Significance:  
Documentation:  
Custom Panel: No

PRODUCTION SCHEDULE

Turn Around Time: 4 to 10 days
Days Performed: Tuesday, Friday
Sites Performed: Quest - Chantilly to Mayo Laboratory
PHL Test Code: MSOT
EPIC Test Code:
Send Out Test Code: 15992
Alternate Test Names: 7 - Dehydrocholesterol; 7 Dehydrocholesterol; 7-Dehydrocholesterol; 7-Dehydrocholesterol Reductase Deficiency; 7DHC; 7-DHC; 8-Dehydrocholesterol; 8DHC; 8-DHC; RSH Syndrome; Smith Lemli Opitz (SLO)
Included Tests: 7-Dehydrocholesterol; 8-Dehydrocholesterol
CPT Coding: 82542

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