C14-OH (3-hydroxytetradecanoylcarnitine)

This test measures the amount of C14-OH, also called 3-hydroxytetradecanoylcarnitine, in your blood. It is one of many acylcarnitine molecules that form when your body processes fats for energy inside the mitochondria. Laboratories typically measure it as part of an acylcarnitine profile using tandem mass spectrometry.

C14-OH helps clinicians see how well long-chain fatty acids are being broken down. Results can be useful in newborn screening and in people of any age who have symptoms suggestive of a fatty acid oxidation problem.

Abnormal C14-OH levels can point to conditions that affect how your body uses fat for energy, such as long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency or mitochondrial trifunctional protein deficiency. Finding these issues early can help prevent serious problems related to low energy supply during illness or fasting.

Your clinician may order this test if there is an abnormal newborn screen, episodes of low blood sugar without a clear cause, muscle breakdown, liver problems, heart issues, or unexplained fatigue. It can also help monitor known metabolic conditions and guide diet and treatment plans that reduce the risk of metabolic crises.

Your result is interpreted together with other acylcarnitines, clinical history, and exam findings. A single elevated or low value does not confirm a diagnosis by itself, because illness, nutrition, and medications can temporarily change acylcarnitine patterns. Patterns across several related markers often provide the clearest picture.

If your result is unexpected, your clinician may repeat testing, order a full acylcarnitine profile, and add urine organic acids or other metabolic studies. Genetic testing may be recommended to confirm or rule out an inherited fatty acid oxidation disorder. If a disorder is suspected, you may receive guidance on avoiding prolonged fasting, adjusting diet, and planning for illness to keep you safe while a specialist completes the evaluation.