Carnitine Metabolism Screening Panel (Plasma)
This test measures levels of carnitine and related compounds in your blood to assess how well your body is converting fats into energy. Abnormal results may indicate issues with fat metabolism or certain genetic disorders.
["Your doctor may order this test if you have symptoms of metabolic problems or genetic conditions affecting carnitine."]
Key facts at a glance
- LOINC
- 109235-2
- Short code
- CARN-SEM
- Synonyms
- Carnitine Msmt Smn
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, wide-mouthed, screw-capped plastic specimen container (semen analysis container)
- Units
- N/A
- Ref low
- 50
- Ref high
- 300
- Fasting
- false
- Population
- adult
- Sex
- male
- Age range
- 18–99 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) or Enzymatic Colorimetric Assay
- CPT
- 82542 (Column chromatography/mass spectrometry, quantitative) or 82180 (Carnitine, quantitative)
- SNOMED
- 442240006
- Specimen volume
- Entire ejaculate specimen (minimum 1-2 mL of seminal fluid required after liquefaction)
- Stability
- Specimen should be delivered to the laboratory within 1 hour of collection and kept at 37°C during transport. After centrifugation, seminal plasma should be frozen at -20°C or -80°C if not analyzed immediately. Stable for 24 hours at 2-8°C and up to 6 months at -80°C.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 48–168 hours
- Order
- routine
What Does This Test Measure?
The carnitine metabolism screening panel typically includes measurements of free carnitine, acylcarnitines (short-, medium-, and long-chain), and sometimes total carnitine. These compounds help transport fatty acids into cells for energy production. Abnormal acylcarnitine patterns can signal metabolic imbalances or inherited disorders like medium-chain acyl-CoA dehydrogenase (MCAD) deficiency.
Why Might Your Doctor Order This Test?
This test is often recommended for individuals with unexplained muscle weakness, fatigue, vomiting, or other symptoms linked to fatty acid metabolism disorders. It may also be used in newborn screening for inherited carnitine deficiency or during evaluation of unexplained liver, kidney, or heart issues.
What Does the Test Involve?
A blood sample is drawn from a vein in your arm. The sample is sent to a lab where carnitine and acylcarnitine levels are analyzed using specialized techniques like tandem mass spectrometry. Results help identify specific imbalances in fat metabolism.
What Are Common Causes of Abnormal Results?
Low carnitine levels may occur due to genetic disorders, kidney disease, or certain medications. Elevated acylcarnitines can signal fatty acid oxidation defects, mitochondrial disorders, or exposure to toxins. Always discuss your full medical history with your provider.
Reference range
Reference ranges for carnitine in semen are not well-established; values should be interpreted in clinical context alongside semen analysis parameters. Generally, total carnitine levels in seminal plasma have been reported in the range of 50-300 nmol/mL in fertile males, though laboratory-specific reference intervals may vary.N/A
Patients should abstain from ejaculation for 2-5 days prior to specimen collection. The specimen should be collected by masturbation into a sterile, wide-mouthed container without the use of lubricants or condoms that may contain spermicidal agents.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Carnitine Panel
Frequently asked questions
What symptoms might this test help diagnose?
How soon will I get my results?
Can I eat or drink before this test?
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