White Blood Cell (WBC) donation, also known as Granulocyte DONATION, is a process that involves collecting white blood cells from a donor’s blood:

Procedure
Apheresis is a procedure that separates blood into its different components, including white blood cells, red blood cells, platelets, and plasma. The donor’s blood is removed in small increments and spun in a centrifuge. The white blood cells are collected into a bag, while the remaining blood components are returned to the donor.