UNLABELLED: The concept of integrated dialysis care is based on the choice of the most optimal method of renal replacement therapy for particular patient in particular period of disease. In many cases peritoneal dialysis (PD) is the initial therapy. PD modalities and regimens are modified according to values of parameters of ultrafiltration and adequacy. The routinely used methods of analysis of peritoneal transport are very useful for general assessment of properties of peritoneum as a dialysis membrane. However, the application of these methods do not guarantee the full assessment of peritoneal transport kinetics of water and substances. Therefore, the capabilities of the most adequate modification are limited. The tests based on mathematical models taking into account the kinetics of intraperitoneal dialysate volume seem to be the right supplement of standard methods. MATERIALS AND METHODS: To illustrate the problem mentioned above, the aim of this study was comparison of peritoneal transport of substances and water in two groups of patients: group I with negative ultrafiltration (UF) (n=14) and group II with positive UF (n=6). In the studied groups peritoneal equilibration test (PET) was done, then the assessment of peritoneal water transport was performed using 125I-HSA as dialysate volume marker, and finally the velocity of peritoneal transport of small molecules expressed by solute mass transport rate (SMTR) coefficient was measured. Patients from both groups belonged to the same category of high-average transporters according to PET criteria. RESULTS: On the base of broaden assessment of peritoneal transport of water and substances it was proved that different, "therapeutic approach" should be applied in studied groups to reach the adequate dialysis. Although in group II the minor modification of continuous ambulatory peritoneal dialysis (CAPD) regimen was desired, the radical change of CAPD schedule or transfer to automated peritoneal dialysis was necessary in cases of patients from group I. CONCLUSIONS: The results of the study indicate that the extended assessment of peritoneal transport kinetics of water and substances increases the capabilities of individualisation of PD program. Therefore, it should be treated as an important element of integrated dialysis care.