Comparison of two different Kt/V methods in continuous ambulatory peritoneal dialysis patients

Dialysis adequacy has gained particular interest for the assessment of the quality of dialysis in patients undergoing hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). Kt/V is used as a test of dialysis adequacy in HD and CAPD patients. The aim of this study was to compare two different Kt/V methods in CAPD patients. A practical method for the calculation of Kt/V will be suggested at the end of this prospective study. The study group included 28 patients. Each patient received CAPD therapy four times per day. During the study, CAPD dialysate samples for a period of 24 hours were obtained by two different methods. One is a modified method for obtaining samples by the patient at home; the other is the conventional method. For study purposes only, we told the patients using the modified method to bring all the bags to the center (contrary to the aim of the modified method). In the first method (modified method), CAPD patients collected 24-hour dialysate and urine samples at home and brought all of the materials to the hospital. A 10 mm3 dialysate sample was drawn from each CAPD dialysate bag, and then a total of 40 mm3 dialysate was mixed in a beaker. A sample of 10 mm3 of dialysate was taken from the mixture in the beaker, and then this dialysate sample, urine, and 5 mm3 venous blood were sent to the laboratory for urea nitrogen (UN) and creatinine level determinations. In addition to these tests, 24-hour dialysate and urine volumes and the patients' weight and height were measured, and Kt/V values were calculated. In the second method (classic method), all the bags from the 24-hour period were collected and mixed in a big bucket, and then a 10 mm3 sample was taken. The remaining procedures were the same as for the first method. Mean Kt/V values were calculated separately for the two methods and were found to be 2.48 by the modified method and 2.52 by the classic method. The results of the two methods were compared with the Wilcoxon paired t-test, which showed no statistically significant difference (p = 0.5228). In conclusion, two different Kt/V methods can be used in CAPD patients. However, the modified method is easily performed, and CAPD patients can collect and take the dialysate and urine samples at home, and bring these materials to the renal unit without transportation problems.