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Order Code POX 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) using serum specimens

 

Aiding in the assessment of peroxisomal function

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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:

1. Fasting: 12 hours, required; Infants and small children should have specimen collected just before next feeding/meal

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

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 serum

Collection Instructions: Centrifuge and aliquot serum into plastic vial.


Specimen Minimum Volume

Serum: 0.15 mL

Specimen Stability Information

Specimen Type Temperature Time
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

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)

Reject 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

 

If the patient has abnormal newborn screening results for X-linked adrenoleukodystrophy, refer to the appropriate American College of Medical Genetics and Genomics Newborn Screening ACT Sheet.(1)

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.