Monoethyl glycine xylidide (MEGX) test evaluation in primary biliary cirrhosis : comparison with Mayo score

To evaluate the clinical and prognostic value of the monoethyl glycine xylidide (MEGX) test in patients with primary biliary cirrhosis (PBC) in comparison with the Mayo score (Mayo). A prospective study. MEGX determinations at enrolment were compared to the Mayo score as well as to conventional clinical and laboratory parameters in 92 patients with PBC. The MEGX test yielded higher basal values in long-term survivors compared to patients that were transplanted or died during the follow up; patients belonging to the last two groups displayed significantly higher Mayo scores at baseline. Although values for prothrombin time, serum albumin, alkaline phosphatase, cholesterol, cholinesterase, and gamma-glutamyltranspeptidase were significantly different in survivors compared to either transplanted or dead patients at univariate analysis, the multivariate analysis demonstrated an independent prognostic value for the MEGX and the Mayo score solely. The best discrimination between probability of death or survival was achieved with a cutoff value of 25 ng/ml for the MEGX test and of 6 for the Mayo score. When plotting both MEGX test and Mayo score, the point distribution displayed a bimodal trend, and the wide range of values given by the MEGX test was observed to supply a more precise assessment of liver reservoir and a better discrimination of progressive changes in liver function; the limited range of the Mayo score for values below 6 could only identify gross deteriorations. Our data show that the asymptomatic progressive functional deterioration occurring during the natural history of PBC can be monitored by the MEGX test because it appears to be able to identify abnormalities prior to the onset of alterations in conventional laboratory and/or clinical parameters which are likely to affect the Mayo score.