Influence of gender on the monoethylglycinexylidide test in normal subjects and liver donors.

The objective of this study was to investigate the effect of gender on monoethylglycinexylidide (MEGX) formation in normal subjects and cadaveric liver donors. The study included 92 male and female healthy volunteers < 45 years of age and 98 age- and sex-matched liver donors from a previous study, whose livers were used for transplantation. Women < 45 years not taking contraceptives showed significantly lower MEGX concentrations 30 min after lidocaine administration than men [median (16-84th percentile)]: 59 micrograms/L (41-70 micrograms/L) versus 81 micrograms/L (58-98 micrograms/L)]. The lowest MEGX 30 min values were observed in women taking contraceptives: 39 micrograms/L (25-48 micrograms/L). Intraindividual variability of serial MEGX tests was moderate (median: 17.8%, n = 8) when measured in female subjects taking no contraceptives and males. Cadaveric liver donors showed significantly higher MEGX 15 and 30 min values compared with normal subjects (p < or = 0.0001). There was no statistically significant difference between MEGX values obtained in male and female cadaveric donors. The urinary excretion of MEGX was similar in male and female normal subjects. Our results suggest that sex-related differences in MEGX formation as well as the influence of contraceptives have to be taken into account when test results from living related liver donors and patients with less advanced chronic liver disease are evaluated. In cadaveric liver donors, however, sex-related differences do not affect MEGX formation.