Sign in →

Test Code VLCFA Very Long Chain Fatty Acid

Clinical System Name

Very Long Chain Fatty Acid

Description

A comprehensive profile that includes C26, C22, C24, C26/C22, C24/C22, phytanic, and pristanic acid analysis.

Sample Requirements

Specimen: Whole Blood

Container(s): Lavender/EDTA

Preferred Vol:  2.0 mL

Minimum Vol: 1.0 mL (0.5 mL for infants)

 

Note: Fasting sample preferred. Serum and heparnized plasma are also acceptable but not preferred.

 

Processing Instructions

Reject due to:

Spin:Y

Aliquot:Y

Temp:-20 C

Storage location: CPA Freezer, BCG  Box

 

Off-site collection: Spin and freeze aliquoted plasma. Ship frozen.

Stability

Temperature Time
Room temp ≤ 2 hr
Refrigerated 24 hrs
Frozen (Preferred) 3 months

 

Availability

STAT Performed TAT
N Weekly 1 week

 

Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.

Performing Laboratory

Seattle Children's Laboratory    

Department

Department:  Biochemical Genetics

Phone Number: 206-987-2216

 

 

Reference Range

C26 0.05 - 0.41 mcg/mL
C22 9 - 33 mcg/mL
C24  7 - 28 mcg/mL
Phytanic < 3.0 mcg/mL
Pristanic < 0.3 mcg/mL
C26/C22

< 0.02

C24/C22 0.6 - 1.1

 

Methodology

Method: GC/MS

Analytical Volume: 0.2 mL

Limitations:

 

Additional Information: Includes C26, C22, C24, phytanic acid, pristanic acid, C26/C24 and C24/C22

Non-fasting, hemolyzed samples, or samples from patients on a ketogenic diet can cause false elevations in VLCFA and phytanic acid. Ketogenic diets high in milk fat rather than vegetable fat cause higher phytanic acid levels.

CPT Codes

82726

Requisition

Biochemical Genetics Requisition

 

On the requisition include clinical information needed for appropriate interpretation.  (Age, gender, diet (e.g. TPN therapy), drug therapy and family history)

Clinical Utility

For evaluation of disorders of peroxisomal biogenesis or peroxisomal metabolism.

 

 

Zellweger

infantile Refsum

RCDP

nALD

X- ALD

Refsum

Classic Adult

Single enzyme; D-Bifunctinal protein

Single enzyme; Acyl-CoA Oxidase

Inheritance

Aut. Rec.

Aut. Rec.

Aut. Rec.

Aut. Rec.

X-linked

Aut. Rec.

   

C26/C22

Elevated

Elevated

Normal

Elevated

Elevated

Normal

Elevated

Elevated

Phytanic

Elevated*

Elevated

Normal/Elevated

(type I )

Elevated

Normal

N/ Elevated

N to increased

Normal

Plasmalogens

Decreased

Decreased

Decreased

(all forms)

 Decreased

Normal

 

Normal

Normal

Pipecolic Acid

Elevated

Elevated

 

Elevated

   

Normal

Normal

Pristanic Acid

Elevated*

Elevated

Normal/Dec

Elevated

Normal 

Normal

N to elevated

Normal

*Phytanic and pristanic can be normal in a neonate with a peroxisomal biogenesis disorder (PBD) since accumulation of branched chain fatty acids occurs through dietary intake. Newborns with PBD may also not have reduced plasmalogens.