Carnitine, Total and Free is a specialized test that measures both total and free carnitine levels to evaluate fatty acid metabolism and energy production. Carnitine is essential for transporting long-chain fatty acids into mitochondria for energy production through beta-oxidation. This test is particularly valuable for evaluating patients with suspected carnitine deficiency, which can cause muscle weakness, cardiomyopathy, failure to thrive, and metabolic disorders. The test helps distinguish between primary carnitine deficiency (genetic) and secondary deficiency (acquired due to other conditions or medications). This test is essential for diagnosing and monitoring patients with metabolic disorders, muscle diseases, and certain cardiac conditions.