Technique

Leukocyte Reduction

WBCs sediment at the interface between red cells and platelet-rich plasma when whole blood collections are separated by centrifugation. Therefore, WBCs typically contaminate both red cell and platelet concentrate components, with concentrations of approximately 10^9 WBCs per product.
WBCs in blood components can mediate febrile transfusion reactions, stimulate HLA alloimmunization in transfusion recipients, and transmit some cell-associated pathogens such as CMV.
Selective leukoreduction filters have been developed capable of at least a 3- log reduction of WBCs in blood components.
Filtration prior to storage reduces WBC breakdown products in the blood component.
All leukocyhte-reduced RBC units must have less than 5 × 10^6 WBCs/U and at least 85% of the original red cell content.

A process in which whole blood is collected through a closed circuit, separated into its constituent elements (often through centrifugation), and specific blood components are retained in collection bags while the remaining blood is returned to the donor or patient.
- Possible to obtain multiple unit-equivalent doses of platelets, plasma, or RBCs from a single donation.
- Because there is limited loss of RBCs during an apheresis donation, plasma and platelet apheresis donors can donate more frequently than whole blood donors.

A citrate-phosphate-dextrose (CPD) solution fortified with adenine, citratephosphate-dextrose-adenine (CPDA-1) became available in the United States in 1978.
Citrate-based anticoagulants are used for both manual whole blood and automated apheresis collections. Citrate chelates ionized calcium in blood, blocking calcium-dependent coagulation in the collection bag and stored component.
Dextrose serves for cell maintenance and phosphate buffers to help retain a stable pH during storage.
Adenine allows for improved maintenance of adenosine triphosphate (ATP) content and RBC viability during storage.
CPDA-1 permits RBC storage for up to 35 days.