The major anticoagulant used in blood product collection and storage. Citrate binds to free calcium and prevents it from interacting with the coagulation system. Citrate works great to keep our blood products from clotting, but it can also cause problems when it is infused into a patient or donor. This is usually not an issue in routine transfusion, but when patients are massively transfused, they may have problems with the citrate binding to their calcium and causing significant hypocalcemia (which may result in neurologic and cardiac issues including arrhythmias and general depression of functions). For blood donors, specifically those undergoing apheresis procedures, mild hypocalcemia may result when the remaining blood components are re-infused to the donor following harvesting of the targeted component(s).