Carnitine, Free and Total, Urine
Ordering Recommendation

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

Tandem Mass Spectrometry
2-9 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
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. 
Ambient: Unacceptable; Refrigerated: Unacceptable; Frozen: 1 month 
Reference Interval
Test Number
Reference Interval
0081307Carnitine, Total, Urine0-5 months: 160-1552 µmol/g creatinine
6-23 months: 231-1710 µmol/g creatinine
2 years and older: 73-731 µmol/g creatinine
0081309Carnitine, Free, Urine0-5 months: 16-922 µmol/g creatinine
6-23 months: 37-1066 µmol/g creatinine
2 years and older: 7-407 µmol/g creatinine
 Carnitine, Esterified, Urine0-5 months: 138-525 µmol/g creatinine
6-23 months: 175-613 µmol/g creatinine
2 years and older: 55-317 µmol/g creatinine
 Carnitine, E/F Ratio, Urine0-5 months: 0.4-6.8
6-23 months: 0.4-5.0
2 years and older: 0.5-7.3

Interpretive Data

Compliance Statement B: For laboratory developed tests not using a RUO kit, and for FDA approved, cleared or 510(k) exempt assays with alterations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

The concentration of esterified carnitine is derived from a mathematical calculation using free and total carnitine.
Hotline History
Component Test Code*Component Chart NameLOINC
0081307Carnitine, Total, Urine17866-5
0081309Carnitine, Free, Urine17867-3
0081310Carnitine, Esterified, Urine28589-0
0081311Carnitine, E/F Ratio, Urine54442-9
* 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.
  • L-Carnitine
  • Urinary Carnitine, Quantitative