Carnitine, Free and Total, Plasma

Additional Information:

Epic order code: LAB815

CPT Code(s):


Collection Procedure:

  • Venipuncture is preferred. Capillary specimens are accurate and acceptable if properly collected.
  • Spin specimens before refrigerating them if blood is collected in a gel tube (PST, PPT). If transport is delayed or specimens are not sent by overnight courier, spin the blood, and seperate and freeze the plasma.

Specimen Requirements:

Type: Blood
Container: Heparin or EDTA
Sample volume: 0.5 mL
Minimum volume: 0.25 mL
Storage: Refrigerate whole blood specimens.
Stability (collection to time of analysis):

  • Ambient: 4 hours
  • Refrigerated: 1 day
  • Frozen: 4 weeks
Rejection criteria:

  • Frozen whole blood
  • Citrate or acid citrate dextrose (ACD) tube


This test is used to evaluate the plasma carnitine status in individuals at risk for carnitine deficiency, due to carnitine transporter deficiency; inherited metabolic disorders; renal insufficiency; valproic acid therapy; and decreased dietary intake.

Limitations: Plasma carnitine concenteration may not correlate with carnitine concentration in tissues (see Debska-Slizien A, et al., J Ren Nutr, 2007; 17:27-81.)


Liquid chromatography – tandem mass spectrometry (LC-MS/MS)


5 – 7 business days