Synthetic Blood; Artificial Blood from Expired Donor Blood. In the context of medical research, expired donor blood refers to blood that has reached the end of its approved storage life and is no longer suitable for transfusion. Research reveals ways to repurpose expired blood for other uses, such as extracting hemoglobin and other "initiatives". Expired donor blood is typically discarded after a certain period, usually 21-35 days for red blood cells; ....... 5-7 days for pl