Alberta Precision Laboratories

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Organization:

Alberta Precision Laboratories

Message Alert:

PLEASE NOTE: This Test Directory is in an interim state and due to changes pertaining to the DynaLIFE transition, performing site for routing has not been updated. Please refer to Laboratory Information System for appropriate routing.

Test Name/Synonym:

Very Long Chain & Branched Chain Fatty Acids (Synonyms: Phytanic, Pristanic, X-linked Adrenoleukodystrophy, X-ALD, XALD, Zellweger Syndrome, Refsum Disease, Peroxisomal Biogenesis Disorders, Peroxisome)

Clinical Indications:

This test is for the investigation of peroxisomal biogenesis disorders and specific peroxisomal fatty-acid oxidation disorders.

This test should be ordered in combination with Pipecolic Acid, Blood or Pipecolic Acid, Urine for the investigation of a peroxisomal biogenesis disorders as an additional, independent measure of peroxisomal function.

This test SHOULD NOT be ordered for the investigation of very long chain acyl-CoA dehydrogenase deficiency, as the enzyme deficiency in that disorder is involved in mitochondrial (not peroxisomal) fatty acid beta-oxidation. For the investigation of very long chain acyl-CoA dehydrogenase deficiency, order Acylcarnitine Profile, Blood.

Test Includes:

Metabolites reported:

behenic (docosanoic) acid (C22:0)
ceratinic (hexacosanoic) acid (C26:0)
lignoceric (tetracosanoic) acid (C24:0)
phytanic (3,7,11,15-tetramethylhexadecanoic) acid
pristanic (2,6,10,14-tetramethylpentadecanoic) acid

Ordering Alert:

Minimum 4 hour fast recommended or as specified by physician.

Patients should avoid eating peanut-containing goods (e.g., peanut butter) 24 hours prior to collection.

Collection Alert:

Hours fasting must be indicated. Recommend collection following a minimum four hour fast or just before next feeding for newborns.
Specimens collected from non-fasting patients will be accepted for testing.

LABID (Connect Care):

LAB4044

Test Code:

CALGARY ZONE	BGLBL; IN BGL TEST NAME FIELD ENTER FATTY ACIDS, VLC
CENTRAL ZONE	MISC
SOUTH ZONE (LETHBRIDGE)	FAVLC
SOUTH ZONE (MEDICINE HAT)	FAVLC1
OTHER ZONES	NOT SPECIFIED

Specimen Type:

Blood

Primary Container:

Green top – Sodium heparin (no gel)

Alternate Containers:

Green top – Lithium heparin (no gel)
Red top – Non-additive (no gel)

Minimum Collection Volume:

0.25 mL plasma or serum

Specimen Collection Requirements:

Collect 1 Sodium Heparin (or alternate) tube.
Indicate length of fast on the requisition.

Test Resources:

Submit request using the applicable requisition or Connect Care online order entry:

Biochemical Genetics Laboratory Requisition

Please ensure all required information, including patient's clinical history/indication, is provided on the requisition.

Stability and Storage:

Frozen: plasma or serum aliquot

Processing:

For ALL collection locations except for Alberta Children’s Hospital (ACH):
1. Centrifuge; If red top tube is collected, allow to fully clot prior to centrifugation.
2. Transfer plasma or serum to aliquot tube.
3. Write "NaHep", "LiHep" or "Red Top" on the aliquot tube label.
4. Freeze aliquot tube.

If collected at ACH outpatient Lab:

The primary tube can be put on ice (ensure not to freeze sample) or refrigerated for routine pick-ups between 08:30 to 14:30, Monday through Friday (excluding holidays).
If specimen is collected after 14:30, process sample as described above.

Transportation:

Transport frozen specimens on dry ice.
Samples must not thaw during transport.

Method:

Gas chromatography-mass spectrometry (GC-MS)

Method and Interpretation of Results:

Saturated very long-chain and branched-chain fatty acids are detected following derivatization (i.e., silylation) using a gas chromatography-mass spectrometry (GC-MS) stable isotope dilution (SID) method with deuterium-labeled internal standards.

Disorders Detectable by very long-chain and branched-chain fatty acid analysis:
1. Peroxisomal Biogenesis Disorders

Zellweger spectrum disorder (encompassing Zellweger syndrome, NALD and infantile Refsum disease)

2. Specific Peroxisomal Enzyme Deficiencies

X-linked adrenoleukodystrophy
acyl-CoA oxidase deficiency (a.k.a., pseudo-NALD)
D-bifunctional protein deficiency
2-methylacyl-CoA racemase deficiency
Adult Refsum disease

Further confirmatory testing is required for some of these conditions, as nonspecific/artifactual findings as well as overlapping patterns may prevent definitive diagnosis in specific cases.

Routine Turn Around Time:

45 days

Testing Schedule:

Monthly

Reference Interval:

Metabolite	Normal Range	Units
C22:0	33 - 96	µmol/L
C24:0	25 - 79	µmol/L
C26:0	0.22 - 1.08	µmol/L
C26:0/C22:0	< 0.020	ratio
C24:0/C22:0	0.44 - 1.16	ratio
Phytanic Acid	< 11.5	µmol/L
Pristanic Acid	< 1.5	µmol/L

Testing Area:

Biochemical Genetics

Performing Site:

Alberta Children’s Hospital

Additional Test Information:

For priority turn-around contact Biochemical Genetics South Laboratory.

Contact Comments:

Biochemical Genetics South 403-955-7379

Last Updated On:

Tuesday, December 20, 2022

Date of Last Review:

Aug 1 2022 12:00AM