Transfusion
Most hospital blood banks also perform testing to determine the blood type of patients and to identify compatible blood products for blood transfusions, along with a battery of tests (e.g. disease) and treatments (e.g. leukocyte filtration) to ensure and enhance quality. Some such procedures can be done "upstream" by the collecting agency, or a contracted laboratory. The increasingly recognized problem of inadequate efficacy of transfusion and post-transfusion complications raises the importance of quality testing and screening; U.S. hospitals spend more on dealing with the consequences of transfusion-related complications than on the combined costs of buying, testing/treating, and transfusing their blood.
Donors are sometimes paid; in the U.S. and Europe, most blood for transfusion is collected from volunteers while plasma for manufacturing is from paid donors.
In the U.S., certain standards are set for the collection and processing of each blood product. "Whole blood" (WB) is the proper name for one defined product, specifically unseparated venous blood with an approved preservative added. Most blood for transfusion is collected as whole blood. Autologous donations are sometimes transfused without further modification, however whole blood is typically separated (via centrifugation) into its components, with red blood cells (RBC) in solution being a commonly used product. Units of WB and RBC are both kept refrigerated at 33.8-42.8 F (1-6 C), with maximum permitted storage periods (shelf lives) of 35 and 42 days respectively.
Red Blood Cell units can also be frozen when buffered with glycerol, but this is an expensive and time consuming process, and is rarely done. Frozen red cells are given an expiration date of up to 10 years and are stored at -85F (-65C).
The less-dense blood plasma is made into a variety of frozen components, and is labeled differently based on when it was frozen and what the intended use of the product is. If the plasma is frozen promptly and is intended for transfusion, it is typically labeled as fresh frozen plasma. If it is intended to be made into other products, it is typically labeled as recovered plasma or plasma for fractionation. Cryoprecipitate can be made from other plasma components. These components must be stored at -0F (-17.7C) or colder, but are typically stored at -22F (-30C).
The layer between the red cells and the plasma is referred to as the buffy coat and is sometimes removed to make platelets for transfusion. Platelets are typically pooled before transfusion and have a shelf life of five days, or three days once the transfusion centre that collected them has completed their tests. Platelets are stored at room temperature (72F=22.2C) and must be rocked. Since they are stored at room temperature in nutritive solutions, they are at high risk for growing bacteria.
Some blood banks also collect products by apheresis. The most common component collected is plasma via plasmapheresis, but red blood cells and platelets can be collected by similar methods. These products have the same shelf life and storage conditions as their manually produced counterparts. An ongoing study allows platelets collected by apheresis to be kept for seven days, but only with specific microbiological testing. The lack of a preservative solution makes a longer shelf life of little use.
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