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Test Code FAPOX Fatty Acid Profile, Peroxisomal (C22-C26), Serum

Reporting Name

Fatty Acid Profile, Peroxisomal, S

Useful For

Evaluating patients with possible peroxisomal disorders, single-enzyme defects of peroxisomal metabolism such as X-linked adrenoleukodystrophy or peroxisomal biogenesis disorders (Zellweger syndrome spectrum)

 

An aid in the assessment of peroxisomal function

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Fasting-overnight (12-14 hours).

2. Patient must not consume any alcohol for 24 hours before the specimen is drawn.

3. Centrifuge and aliquot serum.

Additional Information:

1. Patient's age and gender is required.      

2. Include information regarding treatment, family history, and tentative diagnosis.


Specimen Minimum Volume

0.15 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 92 days
  Refrigerated  15 days

Reference Values

C22:0

≤96.3 nmol/mL

 

C24:0

≤91.4 nmol/mL

 

C26:0

≤1.30 nmol/mL

 

C24:0/C22:0 RATIO

≤1.39

 

C26:0/C22:0 RATIO

≤0.023

 

PRISTANIC ACID

0-4 months: ≤0.60 nmol/mL

5-8 months: ≤0.84 nmol/mL

9-12 months: ≤0.77 nmol/mL

13-23 months: ≤1.47 nmol/mL

≥24 months: ≤2.98 nmol/mL

 

PHYTANIC ACID

0-4 months: ≤5.28 nmol/mL

5-8 months: ≤5.70 nmol/mL

9-12 months: ≤4.40 nmol/mL

13-23 months: ≤8.62 nmol/mL

≥24 months: ≤9.88 nmol/mL

 

PRISTANIC/PHYTANIC ACID RATIO

0-4 months: ≤0.35

5-8 months: ≤0.28

9-12 months: ≤0.23

13-23 months: ≤0.24

≥24 months: ≤0.39

Day(s) and Time(s) Performed

Monday through Friday; 7 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

82726

LOINC Code Information

Test ID Test Order Name Order LOINC Value
POX Fatty Acid Profile, Peroxisomal, S 43677-4

 

Result ID Test Result Name Result LOINC Value
81369 C22:0 30194-5
7143 C24:0 30195-2
7137 C26:0 30197-8
7138 C24:0/C22:0 30196-0
7139 C26:0/C22:0 30198-6
7140 Pristanic Acid 22761-1
7141 Phytanic Acid 22671-2
7142 Pristanic/Phytanic 30550-8
7144 Comment 48767-8

Clinical Reference

1. Moser AB, Kreiter N, Bezman L, et al: Plasma very long chain fatty acid assay in 3,000 peroxisome disease patients and 29,000 controls. Ann Neurol. 1999;45:100-110

2. Wanders RJA: Inborn Errors of Peroxisome Biogenesis and Function. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. New York, McGraw-Hill Medical Division, 2009, pp 323-337

Method Description

Acidic hydrolysis is followed by basic hydrolysis and reacidification. Hexane extraction then proceeds to derivatization with pentafluorobenzyl bromide (PFB). Separation and detection of PFB-esters is accomplished by capillary gaschromatograph-mass spectrometry using electron capture ionization and selected negative ion monitoring. Quantitation is enhanced by the use of stable isotope-labeled internal standards.(Stellard F, ten Brink HJ, Kok RM, et al: Stable isotope dilution analysis of very long chain fatty acids in plasma, urine and amniotic fluid by electron capture negative ion mass fragmentography. Clin Chim Acta. 1990;192:133-144)

Analytic Time

4 days (not reported on Saturday or Sunday)

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK

Method Name

Gas Chromatography-Mass Spectrometry (GC-MS) Stable Isotope Dilution Analysis

Forms

If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.