The manual preparation of leukocyte-poor red cells for transfusion by a new filter.

Standard and buffy-coat-depleted red cell concentrates were filtered through a new cellulose acetate filter with a manual procedure. No residual leukocytes could be detected in 19 of the 21 filtered units. Extracellular hemoglobin after red cell filtration and concentration never exceeded 10 mg per unit. No transfusion reaction occurred in 10 recipients with potent lymphocytotoxic antibodies in their serum and histories of febrile transfusion reactions. This filter allows the preparation of leukocyte-poor red cell units with a safe, simple, and effective manual procedure.