System and methods incorporating replacement fluid maximization

A blood processing system comprising:

• a separator;
• a disposable set configured to cooperate with the separator to separate whole blood passing through the disposable set into plasma and other components, the disposable set attachable to a person to receive whole blood from the person and to return the other components to the person, the disposable set configured to receive replacement fluid from a source of replacement fluid and to deliver the replacement fluid to the person;
• a control circuit;
• and
• an input device comprising a touch screen coupled to the control circuit, the control circuit configured to receive an input via the input device, the input representing a volume of replacement fluid, wherein the touch screen displays a region of the screen bounded by a graphical box and a number displayed within the graphical box, the number being the input representing the volume of replacement fluid,
• wherein the control circuit is further configured to calculate an amount of plasma to be removed based on the person's height, weight, hematocrit, and the input representing the volume of replacement fluid, wherein the control circuit is configured to calculate the amount of plasma to be removed using the weight and height to calculate total blood volume of the person and the hematocrit to calculate the total plasma volume of the person, wherein the control circuit is further configured to control the separator to receive whole blood from the person, separate the whole blood passing through the disposable set, return the other components to the person and deliver the replacement fluid until the amount of plasma to be removed has been achieved.