The number of patients awaiting hepatic transplantation continues to exceed organ donation. As a result, many liver transplant candidates will develop life-threatening complications of their liver disease and not survive the pretransplant waiting period. Recent studies have demonstrated that hepatic lidocaine metabolism into monoethylglycinexylidide (MEG-X) can predict pretransplant survival. The present study was performed to determine if MEG-X could also predict pretransplant complications and thereby be useful in stratifying persons being evaluated for hepatic transplantation. A total of 57 patients with biopsy-proven cirrhosis underwent MEG-X testing. Of 57 patients, 30 (53%) developed life-threatening complications of their liver disease--i.e., variceal bleeding, grade II hepatic encephalopathy or worse, and spontaneous bacterial peritonitis. MEG-X values were greater in persons without complications of liver disease than in persons with complications (25.7 +/- 2.9 versus 14.7 +/- 1.4 ng/ml, respectively). No patients with MEG-X greater than 30 ng/ml developed a major complication. No significant difference in any of the standard liver function tests existed between persons who developed complications and patients who did not. In this group of 57 patients, 4 (7%) died from complications of cirrhosis. Mean MEG-X for patients who died (5.5 +/- 1.6 ng/ml) was significantly less (P < 0.05) than observed for other patient groups. All patients who died had MEG-X values below 10 ng/ml. This suggests that MEG-X testing could be an extremely useful test in the evaluation of patients for hepatic transplantation by identifying persons at increased risk for developing complications of chronic liver disease.