Ordering Recommendation

Useful in the diagnosis of primary carnitine deficiency (carnitine uptake defect) in conjunction with free and total plasma carnitine.

Mnemonic

CARN URINE

Methodology

Tandem Mass Spectrometry

Performed

Tue

Reported

2-9 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation
Collect

Random urine.

Specimen Preparation

Freeze specimen immediately after collection. Transport 5 mL urine. (Min: 2 mL)

Storage/Transport Temperature

CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.

Unacceptable Conditions

Refrigerated or room temperature specimens.

Remarks
Stability

Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 month

Reference Interval

Test Number
Components
Reference Interval
  Carnitine, Total, Urine
Age
µmol/g
0-5 months 160-1552
6 months-23 months 231-1710
2 years and older 73-731

  Carnitine, Free, Urine
Age
µmol/g
0-5 months 16-922
6 months-23 months 37-1066
2 years and older 7-407

  Carnitine, Esterified, Urine
Age
µmol/g
0-5 months 138-525
6 months-23 months 175-613
2 years and older 55-317

  Carnitine, E/F Ratio, Urine
Age
Ratio
0-5 months 0.4-6.8
6 months-23 months 0.4-5.0
2 years and older 0.5-7.3

Interpretive Data

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)

Note

The concentration of esterified carnitine is derived from a mathematical calculation using free and total carnitine.

Hotline History

N/A

CPT Codes

82379

Components

Component Test Code* Component Chart Name LOINC
0081307 Carnitine, Total, Urine 17866-5
0081309 Carnitine, Free, Urine 17867-3
0081310 Carnitine, Esterified, Urine 28589-0
0081311 Carnitine, E/F Ratio, Urine 54442-9
2001266 Creatinine, Urine 2161-8
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • L-Carnitine
  • Urinary Carnitine, Quantitative
Carnitine, Free and Total, Urine