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Test Code LAB0288605 Fatty Acid Profile, Peroxisomal (C22-C26), Serum

Additional Codes

Mayo Test ID
POX

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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) using serum specimens

 

Aiding in the assessment of peroxisomal function

Method Name

Gas Chromatography Mass Spectrometry (GC-MS)

Reporting Name

Fatty Acid Profile, Peroxisomal, S

Specimen Type

Serum


Necessary 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

Reject Due To

Gross hemolysis OK
Gross lipemia Reject
Gross icterus OK
 

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

Interpretation

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. When no significant abnormalities are detected, a simple descriptive interpretation is provided.

 

A profile of elevated phytanic acid, low-normal pristanic acid, and normal very long-chain fatty acids is suggestive of Refsum disease (phytanic acid oxidase deficiency); however, serum phytanic acid concentration may also be increased in disorders of peroxisomal biogenesis and should be considered in the differential diagnosis of peroxisomal disorders.

 

If results are suggestive of hemizygosity for X-linked adrenoleukodystrophy, the calculated value of a discriminating function that more accurately segregates hemizygous individuals from normal controls is included in the report.

 

Positive test results could be due to a genetic or nongenetic condition. Additional confirmatory testing would be required to differentiate between these causes.

Day(s) Performed

Monday through Friday

Report Available

3 to 5 days

Specimen Retention Time

1 month

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

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.