A system and method for determining the amount of fluid to be removed from a dialysis patient is disclosed. The system utilizes sensors and a computer. The computer obtains the input parameters from the sensors, along with information added directly by the user, and performs a forward algorithm to determine a recommended change in patient fluid level. As fluid is removed, the effect of the removal on the parameters is detected by the sensors and re-transmitted back to the computer. The computer then performs a backward algorithm to refine the variables used in the forward algorithm and obtain more accurate results. The system and method provide for changing the amount of fluid removed from the patient based on the results of the algorithm and the data received from the sensors.