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Test Code CARNU Carnitine, Random, Urine

Reporting Name

Carnitine, U

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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 1.5 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

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

Reference Values

Free Carnitine:

77-214 nmol/mg of creatinine

 

Total Carnitine:

180-412 nmol/mg of creatinine

 

Ratio:

Acylcarnitine to free carnitine: 0.7-3.4

Day(s) Performed

Tuesday

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

82379

LOINC Code Information

Test ID Test Order Name Order LOINC Value
CARNU Carnitine, U 100428-2

 

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

Interpretation

When abnormal results are detected, a detailed interpretation is given, including an overview of the results and of their significance, a correlation to available clinical information, elements of differential diagnosis, recommendations for additional biochemical testing and a phone number to reach one of the laboratory directors in case the referring physician has additional questions.

Clinical Reference

1. Zammit VA, Ramsay RR, Bonomini M, Arduini A. Carnitine, mitochondrial function and therapy. Adv Drug Deliv Rev. 2009;61(14):1353-1362

2. El-Hattab AW: Systemic primary carnitine deficiency. In: Adam MP, Ardinger HH, Pagon RA, et al, eds. GeneReviews [Internet]. University of Washington, Seattle; 2012. Updated December 5, 2024. Accessed December 16, 2025. Available at www.ncbi.nlm.nih.gov/books/NBK84551/

3. Almannai M, Alfadhel M, El-Hattab AW. Carnitine inborn errors of metabolism. Molecules. 2019;24(18):3251

4. Longo N., Frigeni M., Pasquali M. Carnitine transport and fatty acid oxidation. Biochim. Biophys. Acta. 2016;1863(10):2422-2435

Report Available

3 to 9 days

Method Name

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