Carnitine Free, Serum by FIA-MS/MS analysis is a laboratory test used to measure free carnitine levels in the blood. Carnitine is a vital compound that plays an essential role in transporting fatty acids into the mitochondria, where these acids are used for energy production. This analysis is considered an important tool in diagnosing and monitoring metabolic disorders associated with carnitine deficiency, which may lead to reduced exercise tolerance, cardiac problems, or muscle weakness. The test relies on the FIA-MS/MS technique, providing high accuracy in measuring carnitine levels. This analysis is recommended in cases of suspected metabolic disorders or in patients who present with unexplained symptoms related to energy and metabolism.