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Test ID SLO Smith-Lemli-Opitz Screen, Plasma

Useful For

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

Genetics Test Information

Smith-Lemli-Opitz syndrome (SLO) is a multiple congenital anomaly disorder caused by defective cholesterol biosynthesis due to deficiency of the enzyme 7-dehydrocholesterol reductase.


Clinical variability has been noted, even within families, and the severity of SLO ranges from severe to mild.


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

Method Name

Gas Chromatography-Mass Spectrometry (GC-MS)

Reporting Name

Smith-Lemli-Opitz Scrn, P

Specimen Type


Specimen Required

Collection Container/Tube:

Preferred: Green top (sodium or lithium heparin)

Acceptable: Lavender top (EDTA), pearl white top (EDTA/gel tubes), yellow top (ACD A) or yellow top (ACD 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

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Frozen (preferred) 90 days
  Refrigerated  90 days

Reference Values

Negative (reported as positive or negative)

Quantitative results are provided when positive.

Day(s) and Time(s) Performed

Tuesday, Friday; 8 a.m. (not reported on Saturday or Sunday)

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
SLO Smith-Lemli-Opitz Scrn, P 33275-9


Result ID Test Result Name Result LOINC Value
81595 Smith-Lemli-Opitz Scrn, P 33275-9
29972 Interpretation 59462-2
29974 Reviewed By 18771-6

Test Classification

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

NY State Approved



If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.