Test Code POX Fatty Acid Profile, Peroxisomal (C22-C26), Serum
Reporting Name
Fatty Acid Profile, Peroxisomal, SUseful 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) using serum specimens
Aiding in the assessment of peroxisomal function
Performing Laboratory
Mayo Clinic Laboratories in RochesterSpecimen Type
SerumNecessary Information
1. Patient's age and sex is required.
2. Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.Specimen Required
Patient Preparation: Fasting 12 hours or more. (Collect specimens from infants and small children just before next feeding)
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
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) Performed
Monday through Friday
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US 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 |
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 gas chromatography 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; Rattay TW, Rautenberg M, Sohn AS, et al Defining diagnostic cutoffs in neurological patients for serum very long chain fatty acids (VLCFA) in genetically confirmed X-adrenoleukodystrophy. Sci Rep. 2020;10[1]:15093)
Report Available
3 to 5 daysReject Due To
Gross hemolysis | OK |
Gross lipemia | Reject |
Gross icterus | OK |
Method Name
Gas Chromatography Mass Spectrometry (GC-MS)
Testing Algorithm
For more information see:
-Newborn Screen Follow-up for X-Linked Adrenoleukodystrophy
-Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm
-Newborn Screening Act Sheet X-Linked Adrenoleukodystrophy: Increased Very Long Chain Fatty Acids
Special Instructions
Forms
1. Biochemical Genetics Patient Information (T602)
2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.