Agreement between the classical urea kinetic model and direct dialysis quantification: importance of urea rebound

From a review of the literature regarding kinetic models used for assessing the adequacy of hemodialysis, no definite conclusions can be drawn as to whether the classical urea kinetic model (UKM) or modified direct dialysis quantification (mDDQ) is more reliable. We compared mDDQ with classical UKM and with a modified UKM that employs an equilibrated urea value. From the theoretical viewpoint, no substantial conflict is found between the two models as regards the dialysis dose, if urea rebound is considered. From the practical viewpoint, in our opinion direct quantification lends itself better for experimental purposes whereas for routine Kt/V evaluation UKM is easier and accurate enough, provided that rebound is taken into account.