Skip to content

Free Carnitine in Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of free carnitine, a compound that helps transport fatty acids into cells for energy production, found in your blood.

Quick summary

["Free carnitine levels can help assess metabolic health and detect certain genetic or metabolic disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
53053-5
Short code
Carnitine Amn-sCnc
Synonyms
Carnitine Amn-sCnc
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like fatigue, muscle weakness, or unexplained weight changes. It could also be used to monitor conditions like mitochondrial disorders, carnitine deficiency, or metabolic syndromes such as fatty acid oxidation disorders.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if it involves a blood draw, but this depends on your provider’s instructions. Avoid strenuous activity on the day of the test.

What Happens During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but the procedure is quick. The blood sample is then sent to a lab for analysis.

What the Results Mean

Results are compared to a reference range specific to your lab. Low levels may indicate carnitine deficiency or metabolic disorders, while very high levels could suggest muscle breakdown or certain liver conditions. Your provider will interpret results in the context of your health history.

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 levels?
Low free carnitine can result from dietary deficiencies (e.g., low-carb or vegetarian diets), certain medications, or genetic disorders that impair carnitine metabolism. It may also occur in conditions like mitochondrial diseases or kidney problems that affect carnitine excretion.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will contact you once they are ready to discuss the findings.
Can I take supplements to raise my carnitine levels?
If your provider suggests it, supplements like L-carnitine may help raise levels, but they should be taken under medical supervision. Overuse or improper dosing can cause side effects, and the right approach depends on your specific condition.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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