Research and development in the blood bank: efforts of a hospital donor center to improve efficiency of in-line leukocyte reduction filters for automated plateletpheresis

Improved removal of white cells with minimal platelet loss by filtration of apheresis platelets during collection

BACKGROUND

Filtration of apheresis platelets to remove white cells (WBCs) requires operator intervention after the collection procedure (postcollection filtration), which may cause variable and unsatisfactory filter performance (WBC removal and platelet loss). The MCS+ LN9000 apheresis system filters platelets through a WBC-reduction filter during each collection cycle (continuous filtration) at a flow rate of 15 to 25 mL per minute. Apheresis platelets obtained by continuous filtration were evaluated in terms of platelet loss, WBC removal, and platelet storage properties and then were compared to unfiltered apheresis platelets and to apheresis platelets that underwent postcollection filtration. Two WBC-reduction filters were tested (LRF6 and LRFXL).

STUDY DESIGN AND METHODS

In 70 apheresis platelets, postcollection filtration was performed by using the LRF6 at flow rates of 80 mL per minute (n = 30) and 50 mL per minute (n = 30) and the LRFXL at 50 mL per minute (n = 10). One hundred fifty-eight apheresis platelets underwent continuous filtration through the LRF6 (n = 58) or the LRFXL (n = 100). Unfiltered apheresis platelets (controls) (n = 30) were obtained by the same collection protocol.

RESULTS

Estimated platelet loss with continuous filtration was 7 percent for the LRFXL and 3 percent for the LRF6. A reduction in the filtration flow rate from 80 to 50 mL per minute with postcollection filtration through the LRF6 resulted in markedly lower WBC levels, with 10 percent versus 57 percent of the apheresis platelets having WBC counts <1 x 10(5), respectively. Additional improvements in WBC removal were found with continuous filtration; 85 percent of the apheresis platelets filtered with the LRF6 and 100 percent of the apheresis platelets filtered with the LRFXL had WBC counts <1 x 10(5).

CONCLUSIONS

Continuous or postcollection filtration of freshly collected apheresis platelets resulted in minimal platelet loss. Better WBC removal from apheresis platelets was obtained with continuous filtration than with postcollection filtration, likely because of the slower flow rate. Platelet storage quality was not affected by filtration.

Pooled platelet concentrates: maybe not fancy, but fiscally sound and effective

For almost two decades, two types of platelet products have been available: pooled random donor platelets (RDP), manufactured from whole blood donations and single donor platelets (SDP), manufactured on apheresis devices. During this period, two trends have occurred--an overall increase in demand for platelets and a preference for the use of SDP. The reasons for the disproportionate increase in the use of SDP relates in all likelihood to supply logistics, perceptions of quality, lack of price sensitivity on the part of prescribing physicians, and minimizing donor exposures in an era of uncertainty and litigation surrounding the allogeneic blood supply. In the cost-conscious 1990s, it is essential to reappraise the situation and perform a critical analysis of the relative value of these products. Such an analysis leads to an inescapable conclusion that preferential use of RDP is the more logical strategy.