One unit of pheresis platelets or single donor platelets is equivalent to 6-8 units of platelets separated from whole blood donations, aka random donor platelets or platelet concentrates. Because red cells and plasma are returned, a plateletpheresis donor can give more frequently than a whole blood donor - once or twice a week. This procedure is ideal for collecting platelets from special donors, be they autologous, designated, HLA-matched, etc. This component is usually processed into Fresh Frozen Plasma or Cryoprecipitate. Granulocytes - The collection of white cells, predominately granulocytes, from a single donor.
Apheresis is the most efficient way to harvest sufficient numbers of granulocytes for transfusion.
The collection of circulating stem cells from a patient following chemotherapeutic conditioning. These cells are used for subsequent transplantation to enhance marrow regeneration. Because therapeutic procedures are controversial and not without risk, clinicians must get approval from the apheresis center medical director before patients are scheduled. See Chapter 8. Any such request to the Blood Bank must be documented in writing and approved by the Blood Bank Director.