Health professionals responsible for the care of dialysis patients are well aware of the complex relationship between treatment variables and patient outcome. Much depends upon the interaction between the patient's blood and the extracorporeal circuit, especially within the hemodialyzer.

Even with systemic heparin anticoagulation, clotting within the dialyzer reduces delivered "dose" of dialysis, increases blood loss, and limits dialyzer reuse.

Dialyzer clotting is further accelerated in cases where heparin anticoagulation is contraindicated, for example, in patients with antibodies to this agent. These complications result in additional staff time required to treat the problems, as well as higher costs for additional supplies (dialyzers, blood lines, etc.).