The present invention concerns an anticoagulation fluid comprising 10-40 mM citrate and 0.1-4 mM 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 a dialysis treatment, and it may be included in a system for regional citrate anticoagulation in an extracorporeal blood circuit.
