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Carnitine (Long-Chain, in Serum/Plasma)

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

This test measures the amount of long-chain fatty acid carnitine in your blood, which helps your cells use energy from fats. Low levels may indicate problems with fat metabolism or certain genetic disorders.

Quick summary

["Long-chain carnitine helps transport fats for energy; abnormal levels may signal metabolic or genetic conditions."]

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

Key facts at a glance

LOINC
53545-0
Short code
Dodeicosanoylcarn CSF-sCnc
Synonyms
Dodeicosanoylcarn CSF-sCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like muscle weakness, fatigue, or unexplained high triglycerides. It’s also used in diagnosing conditions like medium-chain acyl-CoA dehydrogenase (MCAD) deficiency or other inherited metabolic disorders.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours before the draw if your doctor specifies it. Bring your medical history and any medications to your appointment.

What the Test Involves

A healthcare provider will draw blood from a vein in your arm. You may feel a small pinch, but it usually doesn’t cause significant discomfort. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to a reference range for your age, sex, and health status. Low levels may suggest impaired fat metabolism, while very high levels could indicate liver disease or other conditions. Your doctor will discuss findings with you.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Long-chain carnitine level

Frequently asked questions

What could cause abnormal results?
Low long-chain carnitine levels may be linked to genetic disorders (e.g., carnitine palmitoyltransferase II deficiency), mitochondrial disorders, or severe malnutrition. High levels could signal liver disease, fasting, or certain medications.
How might this test affect my treatment?
If your results are abnormal, your doctor may recommend dietary changes, supplements (like L-carnitine), or further testing to identify the underlying cause. Treatment depends on the specific condition diagnosed.
Is this test painful or risky?
The blood draw is generally mild discomfort but not dangerous. Rarely, a bruise or slight swelling may occur at the site. If you have a hard time with needles, let your doctor know so they can prepare accordingly.
  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