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HelpTest Code SLO Smith-Lemli-Opitz Screen, Plasma
Reporting Name
Smith-Lemli-Opitz Scrn, PUseful For
Diagnosing Smith-Lemli-Opitz syndrome (7-dehydrocholesterol reductase deficiency)
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
PlasmaNecessary 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 |
Reference Values
7-DEHYDROCHOLESTEROL
≤2.0 mg/L
8-DEHYDROCHOLESTEROL
≤0.3 mg/L
Day(s) Performed
Tuesday, Friday
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 |
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.
Clinical Reference
1. Donoghue SE, Pitt JJ, Boneh A, White SM. Smith-Lemli-Opitz syndrome: clinical and biochemical correlates. J Pediatr Endocrinol Metab. 2018;31(4):451-459
2. Nowaczyk MJM, Wassif CA. Smith-Lemli-Opitz syndrome. In: Adam MP, Mirzaa GM, Pagon RA, et al., eds. GeneReviews [Internet]. University of Washington, Seattle; 1998. Updated January 30, 2020.Accesses November 02, 2023. Available at www.ncbi.nlm.nih.gov/books/NBK1143/
3. Hall P, Michels V, Gavrilov D, et al. Aripiprazole and trazodone cause elevations of 7-dehydrocholesterol in the absence of Smith-Lemli-Opitz syndrome. Mol Genet Metab. 2013;110(1-2):176-178
4. Genaro-Mattos TC, Tallman KA, Allen LB, et al. Dichlorophenyl piperazines, including a recently-approved atypical antipsychotic, are potent inhibitors of DHCR7, the last enzyme in cholesterol biosynthesis. Toxicol Appl Pharmacol. 2018;349:21-28. doi:10.1016/j.taap.2018.04.029
Report Available
3 to 7 daysMethod 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.