The effect of age on plasma MEGX concentrations.

AIMS: The study was designed to assess the effect age on the monoethylglycinexylidide (MEGX) liver function test. METHODS: Plasma MEGX concentration was measured in 16 young and 17 elderly healthy volunteers 10, 15, 30, 45 and 60 min after intravenous injection of 1 mg kg(-1) lignocaine. RESULTS: Lower MEGX concentrations were noted in elderly subjects. The difference between young and old individuals became increasingly significant as the sampling time was increased, mainly because of a progressive decrease in intersubject variability within each of the two study groups. Linear regression analysis consistently showed that the strength of the relationships between MEGX concentration and age increased with increased sampling time and was maximal at 60 min (r = -0.70; P < 0.0001; reduction in MEGX formation (95% CI) 0.51 (0.33-0.69) ng ml(-1) per year). CONCLUSIONS: These data indicate that the rate of MEGX production declines significantly with age. Therefore, when the results of the MEGX test are to be compared in different study groups, subjects should be strictly matched for age.