Platelet donations are different from blood donations. According
to the American Red Cross, in a platelet donation, a small
portion of your blood (about ¼ of a pint) is collected. This
donation is passed through a cell-separating machine that
collects the platelets. The remaining blood – along with some
saline – is returned back into the donor. Platelet donations are
very beneficial to the recipients. Many patients with weakened
immune systems – like those who are going through chemotherapy –
are in need of platelet donations.