Very Long Chain Fatty Acids [90559]

Message

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

VLNGFA

Alias/See Also

90559

CPT Codes
82726

Includes

Phytanic Acid
Pristanic Acid
Docosanoic, C22:0
Tetracosanoic, C24:0
Hexacosanoic, C26:0
Ratio C24/C22
Ratio C26/C22
Ratio Pristanic/Phytanic
Interpretation

Preferred Specimen

1 mL serum collected in red-top tube (no gel)

Patient Preparation
Fasting Required (overnight fast). No alcohol consumption for 24 hours prior to draw. For pediatric patients, fasting is not required, but sample collection should occur prior to the next meal or scheduled feeding.

Minimum Volume

0.2 mL

Other Acceptable Specimens

Plasma collected in: EDTA (lavender-top) tube

Instructions

Patient age and gender are required for reporting.

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 7 days
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Non-fasting samples • Lipemic samples • Serum separator tube • Hemolysis

Methodology
Gas Chromatography/Tandem Mass Spectrometer

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Tues, Thurs, Sat; Report available: 6-8 days

Reference Range

See Laboratory Report

Clinical Significance

Peroxisomes play a vital role in several metabolic pathways, including the synthesis of plasmalogens and bile acids. They are also involved in the catabolism of Very Long Chain Fatty Acids (VLCFAs), phytanic acid, and pristanic acid. Defects in these pathways usually result in the accumulation in tissues and body fluids of one or more metabolites derived from the blocked metabolic steps. Specific accumulations are used for the differential biochemical diagnosis of numerous peroxisomal disorders. These disorders include (A) Zellweger spectrum disorders of peroxisomal biogenesis, (B) X-linked adrenoleukodystrophy (X-ALD) and its adult form X-linked adrenomyeloneuropathy (X-AMN), (C) Refsum disease (Phytanoyl-CoA hydroxylase Deficiency), and (D) 2-methylacyl-CoA racemase deficiency.

Performing Laboratory

Quest Diagnostics Nichols Institute-San Juan Capistrano, CA

33608 Ortega Highway

San Juan Capistrano, CA 92675-2042

Last Updated: December 7, 2021

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.