Patent ID: 8868357

Claim:
A dialysis system comprising: a disposable cassette including a disposable chamber; a reference chamber; and a controller configured to (i) calculate a volume of air delivered to the disposable chamber using the formula V d = V r * ( Pr 2 - Pr 1 ) ( Pd 1 - Pd 2 ) , wherein V d is the volume, V r is a reference volume of the disposable chamber, and (Pr 2 −Pr 1 ) is a difference between a pressure in the reference chamber before and after equalization, and (Pd 1 −Pd 2 ) is a difference between a pressure in the disposable chamber before and after equalization, (ii) calculate a corrected volume of air delivered to the disposable chamber by multiplying V d by a ratio of a temperature in the disposable chamber to a temperature in the reference chamber T d /T r , and by a ratio of Tr cal /Td cal , wherein Tr cal is a previously measured temperature in the reference chamber and Td cal is a previously measured temperature in the disposable chamber, and (iii) calculate a corrected volume of dialysate pumped by the dialysis system using the corrected volume of air delivered to the disposable chamber.