The further developed adsorption filter Sepacell PL 5/10 II has been evaluated for the white blood cell (WBC) removal from platelet concentrates (PCs) collected using a blood cell separator Fresenius AS 104 (F) or Haemonetics PCS Plus (H). Filtration was carried out according to the manufacturer's instructions by gravity and flow rates of 40-50 ml/min (BT Blood Banking) or 3-5 ml/min (AS Bedside). Mean post-filtration WBC contents under blood bank conditions were (5.63 +/- 6.44) x 10(5) (H) and (0.30 +/- 0.18) x 10(5) (F) for the PL 5 II filter and (3.32 +/- 4.23) x 10(5) (H) and (0.23 +/- 0.05) x 10(5) (F) for the PL 10 II filter; under bedside conditions with low flow rates: (1.31 +/- 1.71) x 10(5) (H) and (0.23 +/- 0.01) x 10(5) (F) for the PL 5 II filter and (0.36 +/- 0.13) x 10(5) (H) and (0.23 +/- 0.01) x 10(5) (F) for the PL 10 II filter. The results suggest that the WBC removal and log reduction correlate with the rates of WBC content of the PCs, the capacity of the filters and the flow rates.