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HelpTest ID POXP Fatty Acid Profile, Peroxisomal (C22-C26), Plasma
Useful For
Evaluating patients with possible peroxisomal disorders, including peroxisomal biogenesis disorders, X-linked adrenoleukodystrophy, and Refsum disease using plasma specimens
Aiding in the assessment of peroxisomal function
Method Name
Gas Chromatography-Mass Spectrometry (GC-MS) Stable Isotope Dilution Analysis
Reporting Name
Fatty Acid Profile, Peroxisomal,PSpecimen Type
PlasmaSpecimen Minimum Volume
0.15 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Plasma | 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
Report Available
2 to 5 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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 US Food and Drug Administration.CPT Code Information
82726
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| POXP | Fatty Acid Profile, Peroxisomal,P | 43677-4 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 36641 | C22:0 | 30194-5 |
| 36642 | C24:0 | 30195-2 |
| 36643 | C26:0 | 30197-8 |
| 36644 | C24:0/C22:0 | 30196-0 |
| 36645 | C26:0/C22:0 | 30198-6 |
| 36646 | Pristanic Acid | 22761-1 |
| 36647 | Phytanic Acid | 22671-2 |
| 36648 | Pristanic/Phytanic | 30550-8 |
| 36649 | Interpretation (POXP) | 59462-2 |
NY State Approved
YesHighlights
This test analyzes very long-chain fatty acids as well as pristanic and phytanic acid to aid in diagnosis of peroxisomal biogenesis disorders, X-linked adrenoleukodystrophy (X-ALD), and Refsum disease.
Reports include concentrations of C22:0, C24:0, C26:0 species, phytanic acid and pristanic acid, and calculated C24:0/C22:0, C26:0/C22:0, and phytanic acid:pristanic acid ratios.
This test is also appropriate for follow-up of an abnormal newborn screen for X-ALD.
Testing Algorithm
The following algorithms are available in Special Instructions:
-Newborn Screen Follow-up for X-Linked Adrenoleukodystrophy
-Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm
For more information, see Newborn Screening Act Sheet X-linked Adrenoleukodystrophy: Increased Very Long Chain Fatty Acids in Special Instructions.
Special Instructions
Forms
If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Necessary Information
1. Patient's age and sex is required.
2. Include information regarding treatment, family history, and tentative diagnosis.
Specimen Required
Patient Preparation:
1. Fasting-overnight (12-14 hours). If fasting not possible for babies or infants, collect specimen prior to next feeding.
2. Patient must not consume any alcohol for 24 hours before the specimen is collected.
Collection Container/Tube:
Preferred: Green top (sodium heparin)
Acceptable: Lavender top (EDTA) or green top (lithium heparin)
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot plasma into plastic vial.