Diffusion-adjusted regional blood flow model (parallel-cum-series representation of physiology) or explaining β
-microglobulin kinetics. Toxin transfer is due to diffusion across capillary endothelium, and blood/plasma circulation causes convective transport. Q
lp, and Q
bp are blood/plasma flows to high flow region (HFR), low flow region (LFR), and dialyzer, respectively. Q
cr and Q
ar are cardiopulmonary and access recirculation, respectively. Shaded compartments represent contact with blood (A – arterial node and V – venous node) .