How do you determine if donated, stored blood is viable?
Blood can be stored as whole blood or packed red blood cells. The constituents of each are different. Which one will be used varies based on the patient, the availability and the situation. Whole blood (not necessarily warm) is used more often when there is massive blood loss, as it contains all the components of blood: clotting factors, platelets, plasma, etc. Packed red blood cells have had the white blood cells removed, most of the plasma, the platelets, etc. It is indicated for routine blood loss and to increase the oxygen carrying capacity of blood. The constituents of each are different.

The primary problems of stored blood viability are red blood cell deformability (red cells are normally very flexible in order to pass through capillaries) and red blood cell fragility (this results in fewer RBCs actually active in the recipient, as RBCs will break apart.) The viability of RBCs in storage depend on factors such as adequate ADP (the energy substrate). When RBSs are less viable for any reason (less deformable, more fragile, or hemolysis has started in the stored blood), this is termed red cell (or red blood cell/rbc) storage lesion.

Though there are probably many questions you may have about storage methods and viability, this will give you an idea of search terms for your reading. Good luck in your research efforts.

Fresh Warm Whole Blood (FWB
2012 Clinical Practice Guide on Red Blood Cell Transfusion
Blood Products
Deformability of stored red blood cells. Relationship to degree of packing
Microvascular perfusion upon exchange transfusion with stored red blood cells in normovolemic anemic conditions
Studies on the preservation of human blood. II. The relationship of erythrocyte adenosine triphosphate levels and other in vitro measures to red cell storageability
Nitric Oxide Scavenging by Red Blood Cell Microparticles and Cell-Free Hemoglobin as a Mechanism for the Red Cell Storage Lesion
Hemoglobin-driven pathophysiology is an in vivo consequence of the red blood cell storage lesion that can be attenuated in guinea pigs by haptoglobin therapy