In the case of peri­phe­ral blood stem cell dona­ti­on, the donor is admi­nis­te­red a growth fac­tor for five days. This encou­ra­ges the stem cells to migra­te into the blood. The cells are then coll­ec­ted from the donor in an out­pa­ti­ent set­ting in a simi­lar way to dialysis.