INADEQUATE WHITE CELL-REDUCTION BY BEDSIDE FILTRATION OF RED-CELL CONCENTRATES

Background: White cell filtration of red cell concentrates is often pe rformed at the bedside, in the ward, with the filter inserted in the b lood administration line. The aim of this study was to evaluate the ef ficiency of this filtration method and compare it to filtration in the blood bank. Study Design and Methods: One-day-old, buffy coat-reduced , hard-packed red cell concentrates in saline-adenine-glucose-mannitol solution were filtered through different filters designed for bedside or laboratory use. With filters designed for bedside use, filtration of red cells was performed under laboratory conditions at fast flow (1 0 min) or under bedside conditions at slow flow (2 hours). The remaini ng white cells were counted microscopically. Filters designed for labo ratory use were evaluated at fast flow, and the number of contaminatin g white cells was counted by flow cytometry. Results: With bedside fil ters, a significantly higher contamination of white cells was found in the units filtered at slow flow than at fast flow, regardless of the filter used. The number of units with >5 x 10(6) white cells was 52 (7 8%) of 67 filtered at slow flow compared to 11 (23%) of 47 at fast flo w, all filters taken together. This difference in white cell contamina tion was mainly due to an increase of polymorphonuclear cells in the r ed cell concentrates filtered at slow flow. With filters designed for laboratory use, 0 to 2 percent of units in = 1448) were contaminated w ith >5 x 10(6) white cells. Conclusion: Bedside filtration for white c ell reduction at slow flow is inefficient for 1-day-old, buffy coat-re duced red cell concentrates.