Free Serum Carnitine
This test measures the amount of free carnitine, a compound that helps transport fatty acids into cells for energy production.
["Free carnitine helps assess metabolic health, especially in conditions affecting fat metabolism."]
Key facts at a glance
- LOINC
- 69422-4
- Short code
- C0-SEM
- Synonyms
- Carnitine Free Smn-sCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, wide-mouthed, screw-capped plastic container (semen collection container); transfer to cryovial preferred for storage
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Fasting
- false
- Population
- adult
- Sex
- male
- Age range
- 18–99 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 82542
- SNOMED
- 395790003
- Specimen volume
- Entire ejaculate (typically 1.5-5 mL); minimum 0.5 mL required for analysis
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 24 hours; Frozen (-20°C or below): up to 3 months for long-term storage; avoid repeated freeze-thaw cycles
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–168 hours
- Order
- routine
Why This Test Might Be Ordered
Your doctor may order a free carnitine test if you have symptoms like muscle weakness, fatigue, or unexplained metabolic issues. It’s also used in diagnosing or monitoring conditions such as mitochondrial disorders, carnitine deficiency, or certain genetic metabolic diseases.
How the Test Works
A small blood sample is taken from your arm. The sample is then analyzed in a lab to measure the concentration of free carnitine in your serum.
What to Expect Before the Test
No special preparation is usually needed, but you may be asked to fast for a few hours before the test if instructed by your healthcare provider.
Common Conditions Monitored
Free carnitine levels can be checked in people with suspected carnitine deficiency, fatty acid oxidation disorders, or those undergoing treatment for metabolic or genetic conditions.
Reference range
Reference ranges for free carnitine (C0) in semen are not well-established; interpret results in clinical context. Generally expected values in normozoospermic males range from approximately 10-50 µmol/L, though laboratory-specific reference ranges should be consulted.N/A
Patient should abstain from ejaculation for 2-5 days prior to specimen collection. Specimen should be collected by masturbation into a sterile container, avoiding lubricants or condoms that may interfere with analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low levels of free carnitine may indicate a deficiency or metabolic disorder, while very high levels could suggest conditions like mitochondrial diseases or certain types of muscle disorders. Your doctor will interpret results in the context of your overall health and symptoms.
Short name
Free Carnitine
Frequently asked questions
What does a low free carnitine level mean?
How long does it take to get results?
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