MEGX is primarily used in the medical field as a metabolite of lidocaine, a local anesthetic. It serves as a biomarker in clinical settings to monitor the metabolism of lidocaine, particularly in assessing liver function. By measuring MEGX levels, healthcare professionals can evaluate the efficiency of liver enzymes, especially in patients with liver disease or those undergoing liver transplantation. This helps in determining the liver's capacity to metabolize drugs and in making informed decisions about drug dosages and treatment plans. Additionally, MEGX testing can aid in diagnosing liver damage or dysfunction, providing critical insights into patient health and guiding therapeutic interventions.