Whole blood may be preserved for up to 21 days without losing its usefulness in blood transfusions; an anticoagulant is added to prevent clotting. Blood plasma, the fluid portion of the blood, may be frozen and/or dried and stored indefinitely. Blood and donors are screened for hepatitis, AIDS, malaria, and other infectious diseases. The potential risk of acquiring AIDS or hepatitis through transfusions has made it a common practice among patients anticipating surgery to "bank" their own blood before it is needed.
Many blood banks also have facilities for apheresis, bone marrow donations, and related procedures. Some centers save umbilical cord blood (blood that is especially rich in stem cells) for use in treatments; however, the cost of preparing and storing such blood is much higher than that of normal blood. Sometimes parents store their newborn's cord blood at a private cord blood bank in case the child has need of it, but the use of one own's cord blood is ineffective or undesirable in many diseases where such blood is used as a treatment.
Most hospital blood banks also perform the testing to determine the blood type of patients and to identify compatible blood products for a blood transfusion. This is sometimes done by the collecting agency or a contracted laboratory instead.
Some hospital blood banks collect blood for transfusion, but this task is often performed by specialized collecting agencies. In some countries, such as Ireland, all blood is collected by a single agency and in others there are multiple blood collection agencies. Many national Red Cross societies, such as the Australian Red Cross, collect blood. Most collected blood is donated, but donors are sometimes paid. In the US and Europe, most blood for transfusion is collected from volunteers and blood (specifically plasma) for manufacturing is from paid donors.
In the US, Standards are set for each product and "Whole Blood" is the proper name for a 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. This product is kept refrigerated at 1-6 C and has a 35 day shelf life.
More frequently, the Whole Blood is spun in a centrifuge to separate it into components. The densest part, the Red Blood Cells, are modified with an additive solution to extend their shelf life, typically to 42 days. These are also refrigerated. Red Blood Cells 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 arbitrary expiration date of ten years and are stored at -80C.
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 -18C or colder, but are typically stored at -30C.
The layer between the red cells and the plasma is referred to as buffy coat and this is sometimes removed to make Platelets for transfusion. Platelets, also known as whole blood or "random" platelets, are typically pooled before transfusion and have a shelf life of five days. Platelets are stored at room temperature (20-24C) and must be agitated. Since they are stored in 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 Platelets by plateletpheresis, but some also collect Red Blood Cells and plasma products 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 any shelf life longer than this of minimal utility.
All of these products are explained in a Circular of Information In the US, they are considered to be drug products, and this is the labeling for the drug.
An early development leading to the establishment of blood banks occurred in 1915, when Richard Lewison of Mount Sinai Hospital in New York City initiated the use of sodium citrate as an anticoagulant. This discovery transformed the blood transfusion procedure from direct (vein-to-vein) to indirect. In the same year, Richard Weil demonstrated the feasibility of refrigerated storage of anticoagulated blood. The introduction of a citrate-glucose solution by Francis Peyton Rous and JR Turner two years later permitted storage of blood in containers for several days, thus opening the way for the first "blood depot" established in Britain during World War I. Oswald Hope Robertson, a medical researcher and U.S. Army officer who established the depots, is now recognized as the creator of the first blood bank.
By the mid-1930s, the Soviet Union had set up a system of at least sixty large blood centers and more than 500 subsidiary ones, all storing "canned" blood and shipping it to all corners of the country. News of the Soviet experience traveled to America, where in 1937 Bernard Fantus, director of therapeutics at the Cook County Hospital in Chicago, established the first hospital blood bank in the United States. In creating a hospital laboratory that preserved and stored donor blood, Fantus originated the term "blood bank." Within a few years, hospital and community blood banks were established across the United States. Willem Johan Kolff organised the first blood bank in Europe (in 1940).
An important breakthrough came in 1939-40 when Karl Landsteiner, Alex Wiener, Philip Levine, and R.E. Stetson discovered the Rh blood group system, which was found to be the cause of the majority of transfusion reactions up to that time. Three years later, the introduction by J.F. Loutit and Patrick L. Mollison of acid-citrate-dextrose (ACD) solution, which reduces the volume of anticoagulant, permitted transfusions of greater volumes of blood and allowed longer term storage.
Carl Walter and W.P. Murphy, Jr., introduced the plastic bag for blood collection in 1950. Replacing breakable glass bottles with durable plastic bags allowed for the evolution of a collection system capable of safe and easy preparation of multiple blood components from a single unit of Whole Blood.
An anticoagulant preservative, CPDA-1 was introduced in 1979. It decreased wastage from expiration and facilitated resource sharing among blood banks. Newer solutions contain adenine and extend the shelf life of red cells to 42 days.
Cryopreservation of red blood cells is done to store rare units, usually for up to 10 years. Truly rare units may be kept even longer . The cells are incubated in a glycerol solution which acts as a cryoprotectant ("antifreeze") within the cells. The units are then placed in special sterile containers in a freezer at very cold temperatures. The exact temperature depends on the glycerol concentration.