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Test ID: PIPA Pipecolic Acid, Serum

Reporting Name

Pipecolic Acid, S

Useful For

Differentiating between disorders of peroxisomal biogenesis (eg, Zellweger syndrome) and disorders with loss of a single peroxisomal function


Detecting abnormal elevations of pipecolic acid in serum

Specimen Type


Necessary Information

Patient's age is required.

Specimen Required

Patient Preparation: Fasting 12 hours or more. (Collect specimens from infants and small children just before next feeding)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

Collection Instructions: Centrifuge and aliquot serum into plastic vial.

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 94 days
  Refrigerated  14 days

Reference Values

<6 months: ≤6.0 nmol/mL

6 months-<1 year: ≤5.9 nmol/mL

1-17 years: ≤4.3 nmol/mL

≥18 years: ≤7.4 nmol/mL

Day(s) Performed


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
PIPA Pipecolic Acid, S 32334-5


Result ID Test Result Name Result LOINC Value
81326 Pipecolic Acid, S 32334-5
29962 Interpretation 59462-2
29964 Reviewed By 18771-6

Clinical Information

Pipecolic acid (PA) is an intermediate of lysine metabolism and is oxidized in the peroxisomes by the enzyme L-pipecolate oxidase. In peroxisome biogenesis disorders (eg, Zellweger syndrome), the activity of this enzyme is lost, resulting in an increase in pipecolic acid levels. In contrast, in peroxisomal disorders involving single enzyme deficiencies such as D-bifunctional protein deficiency, PA is not elevated; therefore, PA analysis is useful for differentiating between these 2 groups of disorders.


Increased pipecolic acid levels may also be seen in alpha-aminoadipic semialdehyde dehydrogenase deficiency (pyridoxine-dependent epilepsy), hyperlysinemia types 1 and 2, and defects in proline metabolism.


Theoretically, a defect in L-pipecolate oxidase can exist and several cases of hyperpipecolic acidemia have been reported, but a specific enzyme deficiency has not been described in any of the patients.


Elevated pipecolic acid levels are seen in disorders of peroxisomal biogenesis; normal levels are seen in disorders with loss of a single peroxisomal function.


Abnormal levels of pipecolic acid should be interpreted together with the results of other biochemical markers of peroxisomal disorders, such as plasma C22-C26 very long-chain fatty acids, phytanic acid, and pristanic acid (POX / Fatty Acid Profile, Peroxisomal [C22-C26], Serum); red blood cell plasmalogens; and bile acid intermediates.

Clinical Reference

1. Gartner J, Rosewich H, Thoms S: The peroxisome biogenesis disorders. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill Medical; 2019. Accessed May 18, 2021. Available at

2. Wanders RJA, Barth PG, Heymans HAS: Single peroxisomal enzyme deficiencies. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill Medical; 2019. Accessed May 18, 2021. Available at

3. Peduto A, Baumgartner MR, Verhoeven NM: Hyperpipecolic acidaemia: a diagnostic tool for peroxisomal disorders. Mol Genet Metab. 2004 Jul;82(3):224-230

4. Braverman N, Raymond G, Rizzo WB, et al: Peroxisome biogenesis disorders in the Zellweger spectrum: An overview of current diagnosis, clinical manifestations, and treatment guidelines. Mol Genet Metab. 2016 Mar;117(3):313-321

Report Available

2 to 9 days

Method Name

Gas Chromatography-Mass Spectrometry (GC-MS)

Testing Algorithm

See Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm in Special Instruction.

Mayo Clinic Laboratories | Genetics and Pharmacogenomics Catalog Additional Information: