- Dialysis adequacy: A single-pool dialyzer clearance multiplied by dialyzer time divided by volume of distribution of urea (Kt/Vurea) of >=1.2 based on a historical value obtained within the prior month in order to ensure the adequacy of dialysis. If Kt/Vurea is not available, then an average of the last 2 values of urea reduction ratio (URR) of at least 65%. NOTE: Only needs confirming at Week -4.