The anticoagulant solutions used in veterinary transfusion practice normally contain citrate (which prevents blood clotting through the chelation of calcium), dextrose (which preserves the glycolytic energy metabolism of the red blood cells), phosphate and adenine.
During the storage of blood in bags, the concentration of 2,3 diphosphoglycerate (2,3 DPG) gradually decreases. 2,3 DPG reduces the affinity of haemoglobin for oxygen, thus favouring its release to tissues. The decrease of 2,3 DPG in stored blood makes this blood less efficient than fresh blood at satisfying tissue oxygen needs. 2,3 DPG is synthesised within 3-8 hours after transfusion and in the following 24 hours reaches 50% of normal levels. This problem is observed mainly in dogs, because cats have low levels of 2,3 DPG.
The anticoagulant solutions most frequently used in veterinary medicine are CPD (citric acid, sodium citrate, phosphate, dextrose), CPD2 and CPDA1 (citric acid, sodium citrate, phosphate, dextrose, adenine). There are blood storage bags commercially available that contain not only anticoagulants, but also nutrient substances (SAG-mannitol) which prolong the survival of red blood cells after their collection.