Background. During dialysis substances are eliminate in particular according to the concentration gradient between plasma and the dialysation solution. Evaluation of a suitable setting of the basic concentration of a substance in the dialysation solution from results of different patients is problematic because of possible individual distortion. The objective of the present work was to suggest and test a practical way of evaluation of group data. Methods and Results. The authors examined a group of 87 dialyzed patients. Using the AAS method they assessed the serum concentrations of Mg, Zn and Cu always before and after dialysis. During dialysis of significant decline of serum Mg occurred (below 0.8 mmol/l). This drop would signalize the need to reduce the concentration gradient, i.e. increase the Mg concentration in the dialysation solution above the current 0.5 mmol/l. However assessment of Mg in red blood cells revealed that dialyzed patients have a significantly increased depot of Mg in the organism (2.67 mmol/l ery as compared with normal 2mmol/l ery) and thus reduction of Mg in serum during dialysis is desirable. Conclusions. The authors suggested and on the basis of Mg tested a graphical way making rapid screening of extensive group data possible when evaluating the adequacy of the composition of the dialysation solution with regard to the concentration gradient of eliminated and retained substances resp. Evaluation of the concentration gradient from group data may be the baseline for optimalization of further individually set parameters of dialysis in individual patients.

        Key words: dialysis, dialysation solution, trace elements, magnesium, zinc, copper.