C12 Dodecanoyl

This test measures dodecanoylcarnitine, also called C12, a medium-chain acylcarnitine found in blood. Acylcarnitines form when fatty acids are linked to carnitine during the process your body uses to convert fat into energy. Measuring C12 helps show how well this energy pathway is working.

C12 is usually assessed as part of an acylcarnitine profile in plasma, serum, or a dried blood spot. The pattern of several acylcarnitines together can point to specific metabolic conditions, especially disorders of fatty acid oxidation.

Healthcare providers use C12 to evaluate for inherited metabolic conditions that affect how the body breaks down fats, and to follow up on newborn screening results or symptoms like fasting intolerance, low energy, liver dysfunction, or muscle pain. C12 can be helpful during illness or metabolic stress, when the body relies more on fat for fuel and abnormalities are more likely to appear.

This measurement can also support monitoring of known fatty acid oxidation disorders, guiding diet, carnitine use, and other treatments. Looking at C12 together with related acylcarnitines helps clarify whether a result reflects a true metabolic problem, a temporary response to diet or illness, or an effect of medications.

Results are interpreted using age-appropriate reference intervals and by comparing C12 with other acylcarnitines. A single borderline or mildly abnormal result can be temporary, especially if you were ill, fasting, or using certain medications. Your clinician may repeat testing when you are well and have eaten, or may order a full acylcarnitine profile, urine organic acids, or genetic testing if a metabolic disorder is suspected.

If results suggest a fatty acid oxidation disorder, your care team may recommend specific nutrition strategies and an action plan for times of illness. For infants and children, consultation with a metabolic specialist is common. Do not change diet or supplements without medical advice; discuss any concerns and next steps with your clinician.