Abstract: Several tests are described for verifying the integrity of the extracorporeal circuit of a medical instrument, such as a dialysis machine. One test verifies the condition of the blood tubing set. Another test verifies that the clamps in the arterial and venous lines adequately occlude the arterial and venous lines. Another test confirms that the arterial and venous lines are properly installed on their respective ports for receiving the lines after the treatment session has ended. In this last test, a fluid such as heated water is then introduced into one of the arterial or venous lines and sent out of the line through its respective port, where it is detected with suitable fluid detection equipment such as a thermistor. The heated fluid and thermistor verify that the arterial line is connected to its arterial port and the venous line is connected to its venous port and that there is an unobstructed fluid path in the blood tubing set.

Abstract: A method of adjusting the final conductivity of a batch of dialysate to bring the conductivity down to a desired level is described. The batch of dialysate is prepared by mixing excess quantities (e.g., 5%) of dialysate solution chemicals with water to form a solution with a conductivity greater than that required for the particular batch. A measurement of the dialysate solution is taken. A precise volume of water is added to the dialysate solution to dilute the dialysate to the proper level. The precise volume of water is calculated from a known or estimated total system, the desired conductivity level and the actual conductivity. The resulting diluted dialysate is at the desired conductivity level. Excess dialysate which may be present in the dialysate circuit or associated tanks is then flushed to a drain. In a hemodialysis embodiment, the excess dialysate may be flushed through the dialyzer into the blood lines to rinse any pyrogens from the extracorporeal circuit.