Determination of peritoneal transport characteristics with 24-hour dialysate collections

Although the 24-hour collection of dialysate provides a very accurate measure of the adequacy of dialysis, it is not known if it can also determine peritoneal membrane transport characteristics. In this prospective study, 101 24-hour dialysate collections were immediately followed by a standard peritoneal equilibration test (PET). Four- and 24-h dialysate-to-plasma (D/P) ratios were determined for creatinine and urea. The correlation coefficients between these two tests were 0.86 for the adjusted D/P creatinine and 0.71 for the D/P urea, whereas the standard errors of estimate were 0.054 and 0.060, respectively. Patients were classified into one of four transport groups on the basis of the mean and standard deviation of the adjusted D/P creatinine values, and these values were similar to those generated from the PET data. Rates of ultrafiltration were also defined for patients undergoing 2.0- and 2.5-L dwells. A survey of a subset of these patients demonstrated that the 24-h collection was preferred to the PET for determining transport characteristics. Therefore, the 24-h dialysate collection can be used to monitor both peritoneal membrane transport characteristics and adequacy. This technique, which has been named the "dialysis adequacy and transport test," has the potential for significant cost savings when it is used for the routine follow-up of both peritoneal transport and adequacy of dialysis.