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Test Code LAB0210856 Smith-Lemli-Opitz Screen, Plasma

Additional Codes

Mayo Test ID
SLO

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

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

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

Smith-Lemli-Opitz Scrn, P

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

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK

Reference Values

7-DEHYDROCHOLESTEROL

≤2.0 mg/L

 

8-DEHYDROCHOLESTEROL

≤0.3 mg/L

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.

Day(s) Performed

Tuesday, Friday

Report Available

3 to 7 days

Specimen Retention Time

1 month

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

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

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.