The use of a hematology analyzer with a new generation of software as an alternative to flow cytometry for enumerating residual white blood cells in blood components

Abstract

BACKGROUNDLeukoreduction of blood components was implemented to reduce transfusion‐associated risks. The detection level for residual white blood cells (rWBCs) required to demonstrate leukoreduction was originally considered too low for hematology analyzers. Developments enabling cell counts in body fluids have, however, renewed interest in rWBC counting. An assessment of Sysmex XN hematology analyzers with software offering automated rWBC enumeration intended for use on blood components was performed.STUDY DESIGN AND METHODSPerformance characteristics were determined using platelet, red blood cell (RBC), and plasma samples spiked with WBCs. Subsequently, components (platelets, n = 1367; and plasma, n = 80) were tested and results compared with flow cytometry, to monitor leukoreduction efficiency to a level of less than 1 × 106/unit. Components identified by flow cytometry as having poor leukoreduction, exceeding this limit, were also tested (platelets, n = 3; and RBCs, n = 10).RESULTSLinearity studies up to 32 WBCs/μL showed good correlation between observed and expected results (R2 > 0.9996). Precision analysis gave an average limit of quantitation of 2 WBCs/μL with coefficients of variation less than 20%. Average carryover was 0.1%. Plain sample tubes were a source of aberrant results with routine components. Using ethylenediaminetetraacetic acid tubes the analyzer gave results greater than 1 × 106/unit in 2.7% of cases compared with 1.4% by flow cytometry, but overall results were within specification, with more than 90% of components having rWBC values below the limit. All incidences of poor leukoreduction, with flow cytometry results greater than 13 rWBCs/μL were correctly identified, with an excellent correlation between results (R2 = 0.9818).CONCLUSIONThe analyzer demonstrated acceptable performance characteristics for enumeration of rWBCs; consequently, additional multisite evaluations are warranted.

Residual red cells in blood components: A multisite study of fully automated enumeration using a hematology analyzer

“…More recently, the Sysmex BB analysis mode on XN‐1000 analyzers has been described as a potential alternative to flow cytometry for rWBC enumeration in blood components 17 . This software also offers the potential for fully automated rRBC enumeration in both plasma and PCs, without any sample preparation.…”

“…Within NHSBT Manchester, components were sampled into EDTA and plain tubes (Greiner Bio‐One) as previously described 17 . Having been processed for routine QM, with appropriate mixing, tubes with sufficient remaining volume were manually inverted twice and placed on the XN‐2000 analyzer, for automatic mixing and rRBC enumeration in the BB mode.…”

“…Thus, Sysmex developed the Blood Bank mode (BB mode), which maintained the hsA mode features but modified the gating strategy for optimal detection of residual cells in blood components and introduced automated mixing and sampling before analysis. This BB mode has been described as a potential alternative to flow cytometry for rWBC enumeration 17 but also offers the ability to simultaneously count rRBCs in both plasma and PCs.…”

Improved accuracy in counting residual white blood cells in red cell concentrates using new blood bank mode software of SYSMEX XN‐1000 hematology analyzer

“…To date, remdesivir presents one such option and can shorten the duration of hospitalization in patients with severe disease. 1 Convalescent plasma (CP) has presented another option, with its use and safety supported by numerous case series and retrospective studies. [2][3][4] While its degree of effectiveness has been variable, there is general agreement that it acts as a supportive adjunctive therapy in patients with moderate to severe disease.…”

“…With great interest we read the article by Blanco et al 1 in which they assessed a Sysmex XN hematology analyzer with Blood Bank mode software (BB mode) for enumerating residual white blood cells in blood components. The authors used spiking experiments to demonstrate the linearity of the hematology analyzer in which they spiked leukoreduced blood products with WBC up to 32 WBCs/ μL.…”