46 B. D. HEDLEY ET AL. DXH 800 PERFORMANCE EVALUATION nucleated red blood cells (NRBCs) is an important and often challenging aspect of the complete blood count (CBC). Conﬁrmation of accuracy of any of these parameters is time-consuming, costly, and the delay in reporting may have a negative impact on patient management. The new Beckman Coulter UniCel DxH 800 Coulter Cellular Analysis System (DxH 800; Miami, FL, USA) complete blood cell counter com- bines advanced hardware technology, innovative computer algorithms, impedance technology, ﬂow cell volume, conductivity, and ﬁve light scatter measure- ments to analyze PLTs, WBCs, and NRBCs. These technologies integrate to deﬁne a new and more accu- rate ‘signature position’ occupied by NRBCs as well as to identify discrete WBC populations and common cellular interferences. This data analysis is performed as part of every routine CBC and WBC differential without the need for additional reagent. Highly accurate automated WBC, PLT, and NRBC counts, especially in the presence of interference, has a large impact in the operational efﬁciency of the hematology laboratory (Schwartz & Stansbury, 1954; Fernandez et al., 2001; La Porta, Bowden & Barr, 2002; Bourner, Dhaliwal & Sumner, 2005; Harrison et al., 2005; Segal et al., 2005; Bodey, 2009). The pres- ence of interfering particles in automated blood cell enumeration often triggers a ‘ﬂag’ for manual review. Although ﬂags are helpful and results in ﬁlm review, this ﬂagging is often not sensitive enough (resulting in false negatives) or misidentiﬁes other cellular types (resulting in false positives) (Brown et al., 2001; Chin- Yee et al., 2001, 2002; Keeney, Brown & Chin-Yee, 2001; Muller et al., 2006; Ghys, Malfait & J, 2009). Inaccurate automated enumeration of any parameter involves the traditional labor-intensive process of manually inspecting and assessing a peripheral blood ﬁlm for each of these parameters. Therefore, technolo- gies that reﬁne automated cell counting so that ﬂag- ging rates are reduced (by increasing speciﬁcity and sensitivity) to those samples which absolutely require manual inspection have the potential to signiﬁcantly improve workload and turn around times. The goal of this study was to evaluate the new Beckman Coulter UniCel DxH 800 cellular analysis system centered upon correlation of WBC, NRBC, and PLT enumera- tion when compared to a predicate analyzer, the Coulter LH 780, and ﬂow cytometry (FCM) refer- ence methods. The protocols and methodologies used in this eval- uation were those of the International Committee for Standardization in Hematology (ICSH) and the Clini- cal Laboratory Standards Institute (CLSI) for reference differential counts and the evaluation of instrument methods (ISLH 1994; Richardson Jones et al., 1996; Koepke et al., 2007). M A T E R I A L S A N D M E T H O D S Evaluation and validation of the DxH 800 cellular analysis system (with software version 1.0.0) was car- ried out in our hospital laboratory, an 800-bed tertiary care hospital with over 700 000 inpatient, outpatient, and emergency visits annually. The hospital provides services for a large region and includes specialized services such as critical care/trauma, cardiology, neurology, cancer care, and transplant (solid and hematopoietic) medicine. Specimens A total of 272 specimens (including morphologically normal and hematological abnormal specimens) were analyzed. All samples were anticoagulated with K2EDTA and were spent routine hematology clinical samples. Samples were stored at room temperature and tested within 8 h of collection. All samples were run initially on the LH 780 in the CDR mode (primary aspiration), followed by similar testing on the compar- ator instrument (DxH 800). WBC, NRBC, and PLT counts were performed on the entire sample set using previously published FCM reference methods (Chin- Yee et al., 2001, 2002; Kaplan, Johnson & Wolfe, 2001; Keeney, Brown & Chin-Yee, 2001). The sam- ples recruited for the study were speciﬁcally chosen so that the analytical range of the DxH 800 was chal- lenged. All samples were morphologically examined and only those found to have NRBCs, giant PLTs, or PLT clumping on a blood ﬁlm were considered truly positive for those abnormalities. DxH 800 The DxH 800 is a fully automated analyzer that pro- vides a CBC, WBC differential, reticulocyte percentage and number, and NRBC enumeration. Advanced signal to noise algorithms have been developed with the goal 2010 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2011, 33, 45–56