The present invention concerns an anticoagulation fluid comprising 10-40 m M citrate and 0.1-4 m M phosphate. The anticoagulation fluid is to be used for regional citrate anticoagulation in an extracorporeal blood circuit. The anticoagulation fluid may be combined with at least one treatment fluid in the dialysis treatment, and it may be included in a system for regional citrate anticoagulation in an extracorporeal blood circuit.
