Sign in →

Test Code LAB2059 Smith-Lemli-Opitz Screen, Plasma

Additional Codes

SLO

Useful For

Diagnosing Smith-Lemli-Opitz syndrome (7-dehydrocholesterol reductase deficiency)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Plasma


Necessary Information


Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.



Specimen Required


Collection Container/Tube:

Preferred: Green top (sodium or lithium heparin)

Acceptable: Lavender top (EDTA), pearl white top (EDTA plasma gel), yellow top (ACD solution A or B)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Centrifuge and aliquot plasma into plastic vial.

2. Send plasma frozen.


Specimen Minimum Volume

0.1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Frozen (preferred) 92 days
  Refrigerated  28 days
  Ambient  14 days
Medical University of South Carolina Note:

On-campus collections: Tube to 99 or deliver to University Extension Hospital Room EH318
Send plasma in plastic vial, Frozen 
 
Off-campus collections: Centrifuge and aliquot within 2 hours. Specimen to be stored/transported at Frozen temp. 

Reference Values

7-DEHYDROCHOLESTEROL

≤2.0 mg/L

 

8-DEHYDROCHOLESTEROL

≤0.3 mg/L

Day(s) Performed

Tuesday, Friday

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SLO Smith-Lemli-Opitz Scrn, P 73852-6

 

Result ID Test Result Name Result LOINC Value
29972 Interpretation 59462-2
610625 7-Dehydrocholesterol 33275-9
610626 8-Dehydrocholesterol 34671-8
29974 Reviewed By 18771-6

Interpretation

Elevated plasma concentrations of 7-dehydrocholesterol (7-DHC) and 8-dehydrocholesterol are highly suggestive of a biochemical diagnosis of Smith-Lemli-Opitz (SLO) syndrome.

 

Mild elevations of these cholesterol precursors can be detected in patients with hypercholesterolemia and patients treated with some antipsychotic or antidepressant medications, including haloperidol, aripiprazole, and trazodone. However, the 7-DHC to cholesterol ratio is typically elevated only in patients with SLO syndrome.

Method Description

The plasma specimen is hydrolyzed and then extracted followed by evaporation to dryness under nitrogen. The sterols are derivatized and then analyzed using selected ion-monitoring electron impact gas chromatography mass spectrometry to quantitate 7-dehydrocholesterol and 8-dehydrocholesterol.(Unpublished Mayo method)

Report Available

3 to 7 days

Specimen Retention Time

1 month

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Forms

1. Biochemical Genetics Patient Information (T602)

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.