The transfusion of donor platelets may be required to treat or prevent bleeding in patients treated with high-dose chemotherapy or radiotherapy who develop severe platelet deficiency. The platelets can be pooled from several unrelated donors and given as “pooled random-donor platelets.” It requires the platelets from at least six one-unit blood donors to significantly raise the platelet count in a recipient. Sufficient platelets can be obtained from one donor by hemapheresis. The latter technique skims off the platelets of large volumes of blood passing through the hemapheresis machine. The red cells and plasma are returned to the donor.

The advantage of single donor platelets is that the patient is not exposed to the antigens on platelets from many different people and is less likely to develop antibodies against donor platelets. HLA-matched platelet transfusion can be given from a related donor with an identical or very similar HLA tissue type. The platelets are collected by hemapheresis.