Preparation of white cell-depleted blood. Comparison of two bedside filter systems.

Numerous techniques have been established for preparing white cell-poor blood, such as centrifugation, sedimentation, freezing, and filtration. All of these methods have disadvantages that restrict their practical use: they are time-consuming, they require the facilities of a blood bank, and the white cell-poor units cannot be stored. Therefore tests have been performed on two filter systems that make possible the depletion of white cells directly at the bedside. Both filters have a high white cell-removal rate. The number of residual white cells in 1 unit of packed red cells was calculated as 1.08 +/- 0.53 x 10(7) in one system and 1.54 +/- 0.71 x 10(7) in the other. The filters do not affect the filtered red cells. Pressure filtration is performed without significant loss of efficiency. One of the systems can filter 2 units via one filter; however, handling the filters is tedious, and both filters are characterized by a low red cell recovery. Despite these disadvantages, the tested filter systems provide an effective device for preparing white cell-poor blood at the bedside. They are a suitable alternative to the conventional methods.