Hemodialysis monitoring system for hemodialysis machines

An improved on-line real time hemodialysis monitoring system for hemodialysis treatment. The hemodialysis monitoring system quantitates the rate and amount of a constituent, such as urea, removed during the hemodialysis treatment by measuring the constituent concentrations as a function of time in the spent dialysate effluent from a hemodialysis machine. A quantity of the spent dialysate effluent is removed from the dialysate effluent waste line periodically for testing. A urea concentration time profile can be analyzed to determined the urea removal, KT/V, URR, SRI and normalized protein catabolic rate (nPCR) indices. The hemodialysis monitoring system preferably can obtain a dialysate sample equilibrated with the blood prior to the start of a hemodialysis treatment. The hemodialysis monitoring system includes a two pool analysis for taking into account the constituent concentration differences in the extracellular and intracellular spaces in the hemodialysis patient during the hemodialysis treatment.