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AABB TECHNICAL MANUAL
temperature ranges from being maintained, the facility should have policies, processes, and procedures in place to relocate the blood components. The secondary storage location may be another on-site refrigerator or freezer, validated storage boxes or coolers appropriate for the blood component and potential prolonged storage time, areas in which the ambient room temperature is monitored, or offsite locations. Because the safety, quality, purity, and potency of the blood components may be affected by delay in relocating to a secondary storage location, it is recommended that the relocation occur before the upper or lower acceptable storage temperature is exceeded. This precaution can be accomplished by setting the alarm points of the storage devices just short of the acceptable storage threshold. Some facilities may choose to use temperature-monitoring indicators applied to each blood component container. Such indicators (depending on the type of various temperature-sensitive labels available) typically monitor the liquid temperature of the immediate inner blood bag, not the liquid core temperature in the unit.5 However, a conservative approach is to use the indicator temperature in deciding component acceptability. The policies, processes, and procedures should specify how the facility will determine the disposition of these blood components. By following a blood banker’s philosophy of “when in doubt, throw it out,” noncompliance issues can be minimized. Biochemical Changes of Stored Blood Red Cells Because blood components are stored in plastic bags of different types and have a variety of added chemicals, the cellular and protein environment is modified from its natural state. Biochemical changes to red cells caused by “storage lesions” are one of the factors determining how long each component may
be stored. For RBC units, at least 75% of the transfused red cells must be present at 24 hours after transfusion.5 The biochemical parameters affected at different days of storage of nonleukocyte-reduced RBCs are shown in Table 9-2. Although the level of 2,3-diphosphoglycerate (2,3-DPG) is nearly absent at the end of storage times, the transfused red cell reestablishes normal levels within 12-24 hours following transfusion.6 Supernatant potassium levels are increased during storage, but because of the small plasma volume in the additive units, even most neonates can tolerate routine transfusion of 15 mL/kg without adverse events.7 Platelets Platelet biochemical changes relate to the production through glycolysis of lactic acid and carbon dioxide from oxidative metabolism of free fatty acids.8 With the advent of newer plastic bags for platelets, pH is maintained above 6.2 by allowing buffering of lactic acid by bicarbonate and diffusion of the carbon dioxide to the environment during agitation.8 Platelet shelf life is limited by functional changes during storage and the risk of bacterial growth. Bacterial contamination has been addressed by the requirement to monitor for the presence of bacterial organisms in platelet concentrates and apheresis platelets. All such components must be tested using various techniques to identify bacterial contamination.3(p13),9 An FDA program is under way at the time of this writing to allow storage of apheresis platelets for 7 days if collected by specific equipment and tested for bacterial contamination using FDA-approved instruments.10 Plasma Components FFP from whole-blood donation may be prepared from the primary centrifugation of whole blood into red cells and plasma or from platelet-rich plasma (PRP) following a hard
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