Free Carnitine (Serum/Plasma Mass Concentration)
This test measures the amount of free carnitine, a compound that helps transport fatty acids into cells for energy production, in your blood.
["Free carnitine levels help assess metabolic health and detect potential deficiencies or imbalances."]
Key facts at a glance
- LOINC
- 2044-6
- Short code
- CARN-SM
- Synonyms
- Carnitine Smn-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, wide-mouthed, screw-capped plastic container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- male
- Age range
- ≥ 18 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 82542 (column chromatography, quantitative carnitine)
- SNOMED
- 252100004 (L-carnitine measurement)
- Specimen volume
- Entire ejaculate (typically 1.5-5 mL)
- Stability
- Analyze within 1 hour of collection at 37°C; if delayed, freeze at -20°C or lower; avoid repeated freeze-thaw cycles
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What Is Free Carnitine?
Free carnitine is a naturally occurring molecule in your body that plays a key role in energy metabolism. It helps move fatty acids from the bloodstream into cells, where they are broken down for energy. Low levels may suggest issues with fat metabolism or certain genetic disorders.
Why Might You Need This Test?
Your healthcare provider may order this test if you have symptoms like fatigue, muscle weakness, or unexplained weight changes, especially if they suspect conditions like mitochondrial disorders, carnitine deficiency, or metabolic syndrome.
Common Conditions Monitored
Free carnitine levels are often checked in people with suspected carnitine deficiency, inherited metabolic disorders, or those undergoing treatment for conditions affecting fat metabolism.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for 8–12 hours before the blood draw if your test involves a fasting sample. Wear a loose shirt for easy access.
Reference range
Reference ranges for carnitine in semen are not well-established; results should be interpreted in the context of clinical evaluation for male fertility and reproductive health.N/A
Patient should abstain from ejaculation for 2-5 days prior to specimen collection. Inform patient about proper collection technique to avoid contamination.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Free Carnitine
Frequently asked questions
What causes low free carnitine?
What does it mean if my levels are high?
Can diet affect free carnitine levels?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy