Very Long-Chain and Branched-Chain Fatty Acids Profile
Also known as: VLCFA
Use
This test is used as an initial screen for disorders of peroxisomal biogenesis and/or function, including X-linked adrenoleukodystrophy and Zellweger syndrome. It measures very long-chain and branched-chain fatty acids to aid in the diagnosis of these conditions. However, the test does not detect essential fatty acid deficiency and should not be used to evaluate nutritional status.
Special Instructions
Fasting specimen is preferred for adults. For infants and children, it is recommended to draw the specimen prior to feeding or 2-3 hours after a meal. Patient history, including age, gender, diet (e.g., TPN therapy), drug therapy, and family history, is needed for appropriate interpretation.
Limitations
This test is limited in its ability to detect essential fatty acid deficiency and should not be used as a measure of nutritional status. It does not substitute for genetic testing or molecular studies that may be required to pinpoint specific genetic defects. Stability issues require that specimens must be frozen, and samples that have been at room temperature for more than 24 hours or refrigerated for more than 48 hours are unacceptable.
New York Approved
Methodology
Mass Spectrometry
Biomarkers
LOINC Codes
- 49263-7
- 22761-1
- 22671-2
- 30194-5
- 30195-2
- 30197-8
- 30550-8
- 30196-0
- 30198-6
Result Turnaround Time
2-9 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
0.5 mL
Minimum Volume
0.2 mL
Container
Green (sodium or lithium heparin) or lavender (EDTA) tube
Patient Preparation
Fasting specimen preferred for adults. For infants and children, draw prior to feeding or 2-3 hours after a meal.
Storage Instructions
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Causes for Rejection
Room temperature specimens greater than 24 hours. Refrigerated specimens greater than 48 hours. Specimens exposed to more than one freeze/thaw cycle.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 72 hours |
| Frozen | 1 month |