A device for blood treatment by extracorporeal circulation including a filter having a first and a second chambers with a semi-permeable membrane, an arterial line connected to the first chamber and associated to a first pump Qb, a venous line out from the first chamber, a first pre-infusion line (109) connected to a citrate container and associated to a second pump Qpre1, a first post-infusion line connected to a calcium solution container associated to a third pump Qpost1, an effluent line at the outlet of the second chamber connected to a drain and associated to a fourth pump Qeff, a CPU including first means programmed to receive the signals output by at least one of the pumps and second means programmed to control third post-infusion pump Qpost1 (121) as a function of the flow rate Qb, Qeff, and Qpre1.
