C10 Decanoyl (Acylcarnitine)

C10 Decanoyl, also called decanoylcarnitine, is a medium-chain acylcarnitine measured in blood. It forms when your body breaks down medium-chain fats and shuttles them into mitochondria for energy production. Laboratories typically measure it as part of an acylcarnitine profile using tandem mass spectrometry.

This test helps show how well your body is performing fatty acid oxidation, an essential pathway for maintaining energy between meals and during illness. It is often used in newborn screening follow-up, as well as in children and adults when a fatty acid oxidation disorder is suspected.

Abnormal C10 levels can point to a problem with fatty acid oxidation, such as medium-chain acyl-CoA dehydrogenase (MCAD) deficiency or related conditions. Clinicians may order this test if there is a history of fasting intolerance, unexplained low blood sugar, recurrent vomiting, lethargy, seizures, muscle breakdown, or if a newborn screen suggests a possible metabolic condition.

Identifying a fatty acid oxidation disorder early allows for practical steps that reduce the risk of metabolic decompensation, especially during infections or prolonged fasting. Even when a genetic condition is not present, changes in C10 can reflect acute illness, diet, or medications, so the result is interpreted alongside symptoms and other laboratory findings.

Your result is assessed together with other acylcarnitines, clinical history, and sometimes urine organic acids or genetic testing. A pattern that includes increased medium-chain species can support a diagnosis of a fatty acid oxidation disorder, but isolated or mild changes can occur with intercurrent illness, recent diet, or certain drugs.

If a result is unexpected, your clinician may repeat testing when you are well, review medications and supplements, and consider a comprehensive metabolic evaluation. If a disorder is confirmed, management usually focuses on avoiding prolonged fasting, having an emergency sick-day plan, and targeted nutrition. Most people do well with these measures when the condition is recognized early.