The authors elaborated a method for assessment of the renal lithium clearance, CLr, the results of which correlate well with the plasmatic clearance (CLp] (r = 0.785, p less than 0.05). This correlation improved substantially after correction of CLr to the clearance of endogenous creatinine, CLcr (r = 0.945; p less than 0.05). The mean values of CLr of the investigated group--26.4 ml/min are in agreement with the results published by other authors. A significant correlation between CLr and CLcr (r = 0.826, p less than 0.05) along with comparison of the intraindividual variability of assessed results indicates that it is better to use as a parameter of sodium absorption from the proximal tubule the fractional lithium clearance rather than absolute values of CLr.

1 interní katedra 1 lékarské fakulty Univerzity Karlovy Praha