Peritoneal equilibration test (PET) is the gold standard for evaluating peritoneal transport, and measurement of the drain volume after 4-h dwell time with glucose 4.25% is a simple means of evaluating failure of ultrafiltration. The study objective was to verify if the measurement of the volume drained after 4 h dwell of icodextrin at 7.5% (ICO), has a better correlation with the parameters of PET. Patients in a peritoneal dialysis program (N = 35) underwent three procedures: PET; determination of the drain volume after a 4-h dwell with glucose 4.25%; and determination of the drain volume after a 4-h dwell with ICO. Among patients who were classified as high transporters, the ultrafiltration volume was greater after ICO use. The ICO ultrafiltration volume correlated negatively with the ratio between the 4- and 0-h dialysate glucose concentrations (D4/D0 ratio, r = −0.579; P = 0.002), correlating positively with the dialysate-to-plasma ratio for creatinine (D/PCr ratio, r = 0.474; P = 0.002). For ICO, the area under the receiver operating characteristic curve was 0.867 and 0.792 for the D/PCr and D4/D0 ratios (P < 0.0001 and P = 0.004, respectively), compared with 0.738 and 0.710 for glucose 4.25% (P = 0.020 and P = 0.041, respectively). A cut-off volume of 141 mL discriminated high/high-average transporters from low/low-average transporters. Volume drained after ICO use better predicts peritoneal transport patterns than does that drained after the use of glucose 4.25%.