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Test 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,P

Specimen Type


Specimen Minimum Volume

0.15 mL

Specimen Stability Information

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

Reference Values


≤96.3 nmol/mL



≤91.4 nmol/mL



≤1.30 nmol/mL


C24:0/C22:0 RATIO



C26:0/C22:0 RATIO




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



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



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 days

Performing 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


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



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.

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.