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Test ID CARNU Carnitine, Random, Urine

Useful For

Evaluation of patients with a clinical suspicion of a wide range of conditions including organic acidemias and fatty acid oxidation disorders


Monitoring carnitine treatment


Carnitine levels are disturbed in primary disorders of the carnitine cycle, or secondary disturbances of carnitine metabolism due to other biochemical disorders.


While plasma or serum carnitine is reduced in primary carnitine deficiency, urine carnitine may be normal or elevated.


Dietary intake (meat, carnitine supplementation) may cause increased carnitine values.


Abnormal results are accompanied by detailed interpretation including recommendations for follow-up testing.

Method Name

Flow Injection Analysis-Tandem Mass Spectrometry (FIA-MS/MS)

Reporting Name

Carnitine, U

Specimen Type


Specimen Required

Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 1.5 mL

Collection Instructions: Collect a random urine specimen.

Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Urine Frozen (preferred) 365 days
  Refrigerated  72 hours

Reference Values


77-214 nmol/mg of creatinine



180-412 nmol/mg of creatinine



Acylcarnitine to free carnitine: 0.7-3.4

Day(s) Performed


Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
CARNU Carnitine, U In Process


Result ID Test Result Name Result LOINC Value
27121 Total 17866-5
27122 Free (FC) 17867-3
15789 AC/FC Ratio 43576-8
21550 Interpretation 59462-2

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 U.S. Food and Drug Administration.

Report Available

2 to 8 days

NY State Approved



If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.