AbstractThe peritoneal equilibration test (PET) is generally accepted as a valuable tool in individualizing continuous ambulatory peritoneal dialysis (CAPD) treatment schedules in adults. However, the classification of peritoneal permeability as described by Twardowski is not available for children due to differences in peritoneal transport abilities. In this paper, we report the results of the PET for 20 patients aged from 1.5 to 24 years (mean 10.3 years), who started CAPD therapy at age 0–15 years, using Twardowski's standardized technique. D/P creatinine (dialysate to plasma ratio of creatinine at 4 h), D/D0glucose (the ratio of dialysate glucose at 4 h dwell time to dialysate glucose at 0 dwell time), and the residual volume (RV) in the abdominal cavity were calculated. The mean and standard deviation values for D/P creatinine and D/D0glucose were of a higher permeability level than those reported in Twardowski's data. Furthermore, a significant correlation of creatinine and glucose with fluid drainage ability of the peritoneum were observed. A large amount of RV (425±125 mL/m2) was detected in the patients' peritoneal cavity and this had a significant correlation with dialysate leak occurrences. The authors suggest that the RV would be an indicator for leaks and especially latent leaks. The cause of a large RV is unknown, but there is a probability that drainage volume and transport rates of metabolites decrease because the concentration of the instilled dialysate is immediately diluted by a large RV within the peritone