C4P Carnitine Plasma Concentration (Mass Concentration)
This test measures the amount of free carnitine in your plasma, a chemical that helps move fatty acids into cells for energy production. Low levels may indicate metabolic issues or certain genetic disorders.
["Free carnitine levels help assess how well your body converts fat into energy."]
Key facts at a glance
- LOINC
- 43580-0
- Short code
- C4PF
- Synonyms
- C4 Pcar-mCnc
- Category
- chemistry
- Sample
- serum
- Container
- Sterile plain tube or red-top vacuum tube without anticoagulant for pericardial fluid collection
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunonephelometry or Immunoturbidimetry
- CPT
- 86160
- SNOMED
- 39517006
- Specimen volume
- 1-2 mL of pericardial fluid
- Stability
- Room temperature: 2 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may recommend this test if you have symptoms like muscle weakness, fatigue, or unexplained weight changes. It’s also used in diagnosing conditions affecting fat metabolism, such as mitochondrial disorders or carnitine deficiency.
What to Expect Before the Test
No special preparation is needed, but you may be asked to fast for 8–12 hours before the test if instructed. Bring any medications or supplements you’re taking to your appointment.
How the Test Works
A blood sample will be drawn from a vein in your arm. The sample is processed to measure free carnitine levels using a specialized laboratory technique.
Possible Results and Interpretation
Results are compared to a reference range specific to your lab. Low levels may signal metabolic dysfunction, while very high levels could indicate liver disease or muscle disorders. Your doctor will discuss findings in the context of your symptoms and medical history.
Reference range
Reference ranges for complement C4 in pericardial fluid are not well-established; results should be interpreted in conjunction with serum C4 levels and clinical context. Pericardial fluid C4 is typically lower than serum levels.N/A
No special patient preparation required prior to pericardiocentesis. Informed consent for the invasive procedure should be obtained.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Plasma Free Carnitine Level
Frequently asked questions
What might cause abnormal results?
Can diet affect this test?
When should I follow up with my doctor?
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