Many factors influence effective clearance. Changes in dialyzer surface area exposure, reduced blood flow, inadequate dialysate flow, recirculation, and other complications can all lead to the under-delivery of the prescribed hemodialysis dose.

The On Line Clearance Monitor (OLC) uses conductivity sensors to measure the pre and post dialyzer change in the sodium concentration of dialysate to determine the effective dialyzer urea clearance.

OLC offers a visual assessment of the adequacy of the treatment provided. Projected adequacy goal attainment is graphically presented on the OLC screen. If the Kt/V drops below a target, the clinician is alerted. This visual aid allows staff to reassess patient condition.