What is carnitine?

Carnitine can refer to L-carnitine, acetyl-L-carnitine and propionyl-L-carnitine. It has an important role in the transportation of long-chain fatty acids into mitochondria, which produce energy for the vast majority of cells in the body. L-carnitine is known as ‘free’ carnitine. In mitochondria, L-carnitine accepts an acetyl group from acetyl-Coenzyme A (CoA), to form acetyl-L-carnitine (acetylcarnitine) and free CoA, which is key for energy production in the Krebs cycle. Without this reaction and subsequent transport of acetyl-L-carnitine out of the mitochondria, build-up of acetyl-CoA results in increased use of carbohydrates for energy production, rather than fatty acids.

Carnitine deficiency can result in problems digesting fats, leading to symptoms including anaemia and low blood sugar. It can also lead to heart, or muscle problems.

Why take the test?

This test checks for the level of free carnitine and total carnitine in the blood. It is used for patients being treated for type-II diabetes, cancer, kidney disease or an enlarged heart. It can also be given to diagnose carnitine deficiency, particularly in babies and infants who may not be able to produce sufficient carnitine themselves.