Complex Compartmental Behavior of Small Water-Soluble Uremic Retention Solutes: Evaluation by Direct Measurements in Plasma and Erythrocytes

Our data indicate by means of direct estimations that the compartmental behaviors of guanidino compounds and urea are substantially different. Hence, we should consider that not all changes in concentrations in uremia and dialysis are representatively reflected by urea kinetics, even when considering other small water-soluble substances, such as the guanidino compounds.