Abstract: A method and apparatus are disclosed for calibrating a sensor for flowing fluid in a system including a dialysis monitor, a fluid inlet and a fluid outlet, the method including applying a first pressure to the flowing fluid and detecting a first flow of the flowing fluid at the fluid input and the fluid output, applying a second pressure to the flowing fluid and detecting a second flow of the flowing fluid at the fluid input and the fluid output, and determining whether any detected differences between the first and second flows are the result of leakage in the system or are caused by the sensor.

Abstract: Methods and apparatus are disclosed for monitoring an infusion pump utilized in a dialysis machine for hemodiafiltration or hemofiltration. The apparatus includes a first flow circuit for a dialysis solution, including a flow meter, a second flow circuit for blood, the dialysis apparatus including a first chamber connected to the first flow circuit, a second chamber connected to the second flow circuit, and a semipermeable membrane separating the first and second chambers, a third flow circuit for withdrawing an infusion solution from the first flow circuit and delivering the infusion solution to the second flow circuit, the third flow circuit including the infusion pump, and a first valve for disconnecting the dialysis apparatus from the first flow circuit and connecting the infusion pump in series with the flow meter in the first flow circuit whereby the expected flow through the infusion pump can be compared with the measured flow through the flow meter.