Schematic illustration of how components are obtained from a single blood transfusion bag
Blood for component therapy is collected into a blood transfusion bag containing single or double satellite bags. An additional satellite bag containing an additive may also be present (but is not illustrated below). Whole blood for platelet-rich plasma (PRP) and fresh frozen (FFP) or fresh plasma production only can be collected into double bag system, whereas whole blood for cryoprecipitate production should be collected into a triple bag system so sterility can be maintained for all products.
After collecting blood from a donor animal, the whole blood can be separated into packed red blood cells and either PRP or FFP (or fresh plasma if it is to be transfused immediately).
Platelet-rich plasma is produced by centrifuging the blood bag (in a special blood bank centrifuge) slowly (e.g. 1,200 g for 2.5 minutes). The PRP is then expressed into the satellite bag, leaving the remaining packed red blood cells in the original collection bag. The PRP can then be used within 8 to 12 hours of blood collection or can be converted into platelet concentrates. Platelet concentrates are produced by centrifuging the PRP, removing the supernatant platelet-poor plasma, leaving the platelets in a small amount of plasma (this is not illustrated above).
Fresh or fresh frozen plasma is produced by centrifuging the blood bag rapidly (e.g. 5,000 g for 5 minutes). The platelet-poor plasma is then separated into the satellite bag and then either used immediately (fresh plasma) or frozen (FFP). The remaining packed red cells are kept in the original blood collection bag.
Cryoprecipitate and cryosupernant are produced from FFP. Fresh frozen plasma is thawed slowly at 4 C for several hours. The cryoproteins precipitate out (and can be seen as a thready precipitate) at this temperature. The bag is then centrifuged at 4 C, the supernatant plasma (cryosupernatant) is removed into the satellite bag, leaving the cryoprecipitate in a small amount of plasma in the original FFP bag. This is then immediately frozen or thawed at 37 C for immediate use.