Use of polyester filters for the preparation of leukocyte-poor platelet concentrates

We studied the usefulness of two polyester leukocyte removal depth filters for the preparation of leukocyte-poor platelet concentrate. The Sepacell R500A removed approximately 92% of the white cells and 98% of the platelets from stored concentrate. In contrast, the Travenol 4C2423 polyester depth microaggregate filter removed less than 1% of the platelets but only 14% of the leukocytes. These findings were obtained with stored (5-day-old) random donor platelets as well as with 16-hour-old platelets collected by apheresis. We conclude that neither of these two leukocyte removal depth filters are suitable for the preparation of leukocyte-poor platelet concentrate; the Sepacell because it removes too many platelets and the 4C2423 because it removes too few leukocytes. The efficiency of cell removal by polyester filters is likely related to alteration of the polyester filter element during fiber manufacture.