A device for performing regional citrate anticoagulant dialysis of a patient's blood in an extracorporeal dialysis circuit comprising: a dialyzer having semi-permeable dialysis membranes and a dialysate chamber surrounding the membranes, a dialysate containing citrate and calcium in an amount sufficient to eliminate the need for calcium to be added to the patient's blood downstream of the dialyzer; the dialysate chamber of the dialyzer configured to flow the dialysate therethrough; a citrate infusion location upstream of the dialyzer for introducing citrate into the blood in the extracorporeal dialysis circuit; and a processor configured to: determine a blood flow rate from and back to the patient through the extracorporeal dialysis circuit, determine a flow rate of the dialysate, the dialysate including a predetermined amount of calcium and a predetermined amount of citrate, compute a serum concentration of ionized calcium in the blood of the patient, compute a concentration of citrate in the blood of the patient, and compute one or more amounts of citrate to be introduced into the blood at the citrate infusion location such that ionized calcium is reduced upstream of the dialyzer to a concentration that is sufficiently small to reduce clotting of the blood in the extracorporeal circuit and such that a need for calcium addition downstream of the dialyzer is eliminated and such that a need for monitoring of systemic ionized calcium is eliminated, the dialyzer configured to dialyze blood flowing through the extracorporeal circuit, said blood containing citrate introduced at the citrate infusion location. a dialyzer having semi-permeable dialysis membranes and a dialysate chamber surrounding the membranes, a dialysate containing citrate and calcium in an amount sufficient to eliminate the need for calcium to be added to the patient's blood downstream of the dialyzer; the dialysate chamber of the dialyzer configured to flow the dialysate therethrough; a citrate infusion location upstream of the dialyzer for introducing citrate into the blood in the extracorporeal dialysis circuit; and a processor configured to: determine a blood flow rate from and back to the patient through the extracorporeal dialysis circuit, determine a flow rate of the dialysate, the dialysate including a predetermined amount of calcium and a predetermined amount of citrate, compute a serum concentration of ionized calcium in the blood of the patient, compute a concentration of citrate in the blood of the patient, and compute one or more amounts of citrate to be introduced into the blood at the citrate infusion location such that ionized calcium is reduced upstream of the dialyzer to a concentration that is sufficiently small to reduce clotting of the blood in the extracorporeal circuit and such that a need for calcium addition downstream of the dialyzer is eliminated and such that a need for monitoring of systemic ionized calcium is eliminated, determine a blood flow rate from and back to the patient through the extracorporeal dialysis circuit, determine a flow rate of the dialysate, the dialysate including a predetermined amount of calcium and a predetermined amount of citrate, compute a serum concentration of ionized calcium in the blood of the patient, compute a concentration of citrate in the blood of the patient, and compute one or more amounts of citrate to be introduced into the blood at the citrate infusion location such that ionized calcium is reduced upstream of the dialyzer to a concentration that is sufficiently small to reduce clotting of the blood in the extracorporeal circuit and such that a need for calcium addition downstream of the dialyzer is eliminated and such that a need for monitoring of systemic ionized calcium is eliminated, the dialyzer configured to dialyze blood flowing through the extracorporeal circuit, said blood containing citrate introduced at the citrate infusion location.