Monoethylglycinexylidide formation measurement as a hepatic function test to assess severity of chronic liver disease.

Objectives: Monoethylglycinexylidide (MEGX) is the main lidocaine metabolite and its formation depends on liver microsomal activity. MEGX formation was studied in comparison with the histological score of chronic hepatitis and with the clinical score (Child-Pugh) of cirrhosis. Furthermore, we evaluated its ability to distinguish between the two liver diseases. Methods: We studied 284 patients: 130 with chronic hepatitis (on the basis of the histological activity index, 45 had mild chronic hepatitis, 54 had moderate chronic hepatitis, and 31 had chronic hepatitis with cirrhosis) and 154 with cirrhosis (49 Child-Pugh's class A, 78 class B, and 27 class C). MEGX formation was evaluated 15, 30, and 60 min after lidocaine administration. Results: MEGX formation showed a stepwise decline corresponding to worsened liver disease. MEGX values were related both to the histological score in chronic hepatitis and to the clinical score in cirrhosis. Significantly lower values were found in females < 50 yr of age than in males of the same age. The MEGX test showed great efficacy in discriminating between chronic hepatitis and cirrhosis compared with standard liver tests. Conclusions: Measurement of MEGX formation proved to be a safe test, allowing us to show that functional subgroups can be identified both in chronic hepatitis and in cirrhosis. Thus, this test could integrate both the histological grading of chronic hepatitis and the clinical staging of cirrhosis.