The removal-based SRI can be applied to the CAPD setting, and this new index of dialysis dose is numerically equal to the KT/V for a continuous therapy like CAPD. This is not true for hemodialysis where the SRI is numerically lower than the KT/V. If therapy prescriptions for CAPD, APD, and HD are all adjusted to provide the same removal at the same predialysis BUN, then the values of SRI will be the same in all three modalities despite differences in the frequency and duration of the therapy modalities. This is a major advantage of the SRI over KT/V in that it provides a unified, intuitive basis for comparing disparate therapies. The peak concentration hypothesis is implied in this approach because the therapies have equivalent SRI when there is matching of the peak predialysis BUN of APD and HD with the steady-state BUN of CAPD. However, if KT/V is used as the basis of comparison for different modalities, the weekly KT/V has to be adjusted with a scaling factor that varies with the frequency of dialysis. A different scaling factor will apply for daily APD versus that for thrice-weekly HD. The requirement of a scaling factor and the variability of this factor with therapy frequency complicate therapy comparisons based on KT/V. This complication is avoided with the SRI. Further, as detailed in a prior publication (1), the SRI has several advantages over the KT/V index for hemodialysis therapy, which include the avoidance of clearance corrections for access recirculation, cardiopulmonary recirculation, and compartmental disequilibrium.(ABSTRACT TRUNCATED AT 250 WORDS)