System (1) for extracorporeal blood treatment, with:a haemofiltration device (2),means (3) for pumping blood through the haemofiltration device (2),citrate addition means (4) arranged upstream of the haemofiltration device (2) in the direction of blood flow configured to add citrate to the blood,calcium addition means (5) arranged downstream of the haemofiltration device (2) in the direction of blood flow configured to add calcium to the blood, and control means (6) configured to activate or inactivate the citrate addition means (4) and/or the calcium addition means (5), wherein the control means (6) is adapted to activate the citrate addition means (4) at or before the beginning of blood treatment, to determine the elapse of a first time period (t1) after the blood treatment is actavitated and to continue to operate the citrate addition means (4) until the end of blood treatment, at which point in time the citrate addition means (4) is inactivated, wherein the control means (6) is further adapted to activate the calcium addition means (5) after the first time period has elapsed, when total extracopropreal blood volume in the system has been filtered and citrate treated, to continue to operate the calcium addition means (5) in an active state during blood treatment and to continue to operate the calcium addition means (5) in an active state after the end of blood treatment, until a second time period (t2) has elapsed after the end of treatment.
