Blood Delivery System
The blood supply is defined by the relationship between its two key participants: regional blood centers and hospital transfusion services.
Regional blood centers collect and provide more than 90 percent of the blood supply. Blood centers generally have responsibility for providing blood services to a geographically contiguous group of hospital-based transfusion services. The relative responsibilities and roles of regional blood centers and hospital transfusion services in the management of the blood supply are illustrated below.
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n basic terms, regional blood centers are responsible for recruiting donors, collecting blood, ABO typing, infectious disease testing, component manufacturing and distribution of red cells to hospital transfusion services. The hospitals then retest each unit for ABO blood group, crossmatch the units to the appropriate patients and perform the actual transfusions. While this process is simple conceptually, it is complicated by three important factors:-
The high demand for group O blood due to its universal transfusability, hospital transfusion policies and the suitability of group O red cells for emergency use where the delays caused by typing and matching are not acceptable.
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The criticality of matching ABO blood groups between donor and recipient in order to avoid potentially fatal transfusion reactions.
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The relatively short 42-day shelf life of red cells, after which they may not be transfused.
These factors complicate the collection and matching of blood to an individual recipient to such a degree that an extremely complex logistical system has emerged. This is demonstrated in the figure below, which illustrates various pathways that make up the current blood supply and distribution system.
The balancing of the inventory of units of red cells is extraordinarily complex and at the center of this complexity is the regional blood center. On a daily basis, the regional blood center must match the demand for blood by ABO group from its hospital customers with the available supply held at the blood center, at its hospital customer sites and at other regional blood centers. Individual red cell units are constantly being moved within this system in order to match daily variations in supply and demand. In fact, individual units are often moved several times within this system before finally being transfused. Even with the best efforts of the participants in this process to insure that each unit collected is ultimately transfused, it is estimated that four to six percent of all units collected outdate before transfusion and must be discarded.
Tests to confirm ABO group specificity are performed repeatedly within this process as well. In order to avoid clerical errors, to assure transfusion safety and to comply with regulatory guidelines, red cell units must be retested to reconfirm ABO group specificity each time a unit is moved. Even after units arrive at the hospital where they are ultimately transfused, they are subjected to multiple retests for ABO confirmation to insure patient safety.
Ultimately, the critical nature of matching donor and recipient by ABO group is the underlying factor that drives the complexity of the blood transfusion process, and with this complexity comes cost. Since the company’s unique and proprietary technology could convert all group A, B and AB red cells to group O, most of the costs and complexities caused by managing multiple blood groups would be eliminated. Conceptually, the process by which the blood supply could be converted to all O using ZymeQuest’s conversion technology is illustrated below.
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