7-Dehydrocholesterol
Label Mnemonic: 7DHCH
Epic Lab Code: LAB2516
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Plasma
Specimen Instructions:
Patient should be fasting 12 hours or more before collection. Pediatric patients draw before next feeding.
Collection Medium:
Green top tube 4 mL (Na Heparin)
Alternate Collection Media:
Lavender top tube 3 mL (EDTA)
Minimum:
Preferred Minimum: 0.5 mL sodium heparin plasma from a fasting patient
Absolute Minimum: 0.2 mL
Delivery Instructions:
Deliver to laboratory immediately after collection.
Turn Around Time:
3 days upon receipt at reference laboratory
Reference Range:
Negative (reported as positive or negative)
Quantitative results are provided when positive
Comments:
Useful for diagnosis of 7-dehydrocholesterol reductase deficiency (Smith-Lemli-Opitz syndrome). It is NOT used in the routine assessment of nutritional lipid status. The enzymatic tests for measuring plasma cholesterol quantitate all 3 hydroxysterols and are unreliable for diagnosis for SLO.
Methodology:
Gas Chromatography-Mass Spectrometry (GC-MS)
CPT Code:
82541