Comparison of peritoneal equilibration test with 99mTc-DTPA excretion in the assessment of peritoneal permeability

Assessment of peritoneal permeability is necessary for successful management of end-stage renal disease (ESRD) patients by continuous ambulatory peritoneal dialysis (CAPD). The objective of this study was to develop an alternative method of assessing the peritoneal permeability and to compare this method with the conventional method, the peritoneal equilibrium test, first described by Twardowski in 1987. Twenty patients undergoing regular CAPD were included in this study. Before starting the peritoneal dialysis, 370 MBq (10 mCi) technetium-99m diethylene triamine penta-acetic acid (^99mTc-DTPA) was injected intravenously. A standard dose of the same quantity was kept and used later for calculations. At the end of 4 h, a dialysate fluid sample (1 ml) was collected and the total dialysis effluent fluid volume was measured. Excretion of ^99mTc-DTPA into the dialysate fluid as a percentage of the injected dose was calculated. Simultaneously, standard peritoneal equilibrium test values were recorded for comparison. Peritoneal excretion of ^99mTc-DTPA ranged from 8% to 25% of the injected dose, depending on the peritoneal membrane permeability. When the results were compared with the conventional method, a good correlation (r=0.79) was found. This innovative radionuclide technique is a simple and convenient method to assess the peritoneal membrane permeability and can be used as an alternative to the peritoneal equilibrium test, which is very cumbersome and associated with many limitations.