Ordering Recommendation

Useful in the diagnosis of primary carnitine deficiency (carnitine uptake defect). Monitor carnitine status.

Mnemonic
CARN F&T
Methodology

Tandem Mass Spectrometry

Performed

Tue-Sat

Reported

1-4 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Green (sodium or lithium heparin). Also acceptable: Plain red.

Specimen Preparation

Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum or plasma to an ARUP Standard Transport Tube and freeze immediately. (Min: 0.2 mL) Avoid hemolysis.

Storage/Transport Temperature

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

Unacceptable Conditions

Room temperature specimens. Specimens refrigerated greater than 12 hours.

Remarks
Stability

After separation from cells: Ambient: Unacceptable; Refrigerated: 12 hours; Frozen: 1 month (avoid repeated freeze/thaw cycles)

Reference Interval
Age
Carnitine, Free, Serum/Plasma Carnitine, Total, Serum/Plasma Carnitine, Esterified, Serum/Plasma
Carnitine E/F Ratio, Serum/Plasma
1 - 31 days 15 - 55 µmol/L 21 - 83 µmol/L 4 - 29 µmol/L 0.2 - 0.8
32 days-12 months 29 - 61 µmol/L 38 - 73 µmol/L 7 - 24 µmol/L 0.1 - 0.8
13 months - 6 years 25 - 55 µmol/L 35 - 90 µmol/L 4 - 36 µmol/L 0.1 - 0.8
7 years -20 years 22 - 63 µmol/L 31 - 78 µmol/L 3 - 38 µmol/L 0.1 - 0.9
21 years or older 25 - 60 µmol/L 34 - 86 µmol/L 5 - 29 µmol/L 0.1 - 1.0

Interpretive Data



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
0080064 Carnitine, Esterified, Serum/Plasma 19074-4
0080066 Carnitine, Free, Serum/Plasma 14286-9
0080067 Carnitine, Total, Serum/Plasma 14288-5
0081148 Carnitine E/F Ratio, Serum/Plasma 40869-0
* 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
  • Esterified carnitine
  • Free and Total Carnitine
  • L-Carnitine Free and Total
Carnitine, Free & Total (Includes Carnitine, Esterified)