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Immunology & Autoimmune
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Currently under review
Pending specialist review and validation.
C14:1 tetradecenoyl, also called tetradecenoylcarnitine, is a long‑chain acylcarnitine measured in your blood. It reflects byproducts formed when your body breaks down long‑chain fats inside mitochondria. Laboratories typically measure it using tandem mass spectrometry on a small blood sample or a dried blood spot.
This marker is part of an acylcarnitine profile that helps assess how well long‑chain fat oxidation is working. It is commonly included in newborn screening programs and in evaluations for suspected inherited metabolic conditions across all ages.
Higher C14:1 can suggest a fatty acid oxidation disorder, most notably very long‑chain acyl‑CoA dehydrogenase deficiency, and sometimes other long‑chain defects such as trifunctional protein deficiency or carnitine palmitoyltransferase II deficiency. These conditions can lead to low blood sugar without typical ketones, muscle breakdown, and heart or liver problems during stress.
Clinicians order this test in newborn screening and in people who have episodes with fasting, illness, heavy exercise, or anesthesia. Recognizing a problem early allows tailored nutrition, avoidance of prolonged fasting, and emergency plans that reduce the risk of serious complications.
Your result is interpreted together with the full acylcarnitine pattern, your symptoms and history, and sometimes urine organic acids or other metabolic tests. A single elevated value does not confirm a diagnosis. Temporary changes can occur with acute illness, poor intake, special diets, or certain medicines, and levels can look typical between episodes.
If your result raises concern, your clinician may repeat testing, review a comprehensive acylcarnitine profile, and arrange confirmatory studies such as genetic testing or enzyme analysis. For newborns, maternal health and feeding status can influence early results, so follow‑up testing is routine after an abnormal screen. Ask your care team about sick‑day plans and whether nutrition changes or supplements are recommended for prevention and safety.
Reference intervals vary by laboratory, analyzer, methodology, population, and units. The ranges shown here are for education only. Always interpret your results against the reference interval printed on your own lab report.
In newborns, the first days of life and recent feeding strongly influence acylcarnitine levels. Early samples or poor intake can shift results and may prompt repeat testing.
Fever, infections, dehydration, or prolonged fasting increase fat breakdown and can raise long‑chain acylcarnitines, potentially mimicking an inherited disorder.
Drugs such as valproate, some antibiotics, or antiretrovirals, and supplements like carnitine or medium‑chain triglyceride oils can alter acylcarnitine patterns.
Very low‑carbohydrate or ketogenic diets, high fat intake, or recent heavy exercise can change fat oxidation and affect C14:1 levels.
Results can vary between dried blood spot and plasma. Proper collection, prompt drying, and cold storage help prevent degradation and misleading values.
In newborn screening, maternal carnitine status, pregnancy complications, or maternal medications can influence an infant’s initial acylcarnitine results.
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