Figure 1. Leukocyte enumeration. (a) Leukocyte counts for all samples collected (n = 264) on the DxH 800 and LH 780 vs. ﬂow cytometry (FCM). r2 Values for DxH 800 vs. LH 780 and DxH 800 vs. FCM were 0.998 and 0.994, respectively. (b) Leu- kocyte counts in the presence of cellular interference on the DxH 800 compared to the LH 780 and FCM. r2 Values for DxH 800 vs. LH 780 and DxH 800 vs. FCM were 0.996 and 0.990, respectively. (c) Leukocyte counts in the presence of nucle- ated red blood cells (manually conﬁrmed) on the DxH 800 compared to LH 780 and FCM. r2 Values for DxH 800 vs. FCM and LH 780 vs. FCM were 0.998 and 0.992, respectively. Parameter WBC (·109/l) RBC (·1012/l) HGB (g/l) MCV (ﬂ) PLT (109/l) NRBC (/100 WBC) Retic (%) (a) (c) Low limit DxH 800 0.000 0.000 0.00 50.00 0.0 0.00 0.000 Table 1. The range of linearity of the new DxH 800 cellular analysis system and the LH 780 WBC, white blood cell; PLT, platelet; NRBC, nucleated red blood cell. Lines of best ﬁt were generated for all the data (Figure 1a) conﬁrming that the new DxH 800 demon- strates extremely good correlation with the predicate reference LH 780 analyzer and the reference FCM (r2 = 0.998 and 0.994, respectively). Analysis of the WBC counts for accuracy showed there was no signif- icant difference between the DxH 800 and the LH 780 or FCM (P = 0.918, ANOVA). The DxH 800 showed no statistical difference between results when compared to both the LH 780 (P = 0.762) and FCM (P = 0.693) with no signiﬁcant bias in leukocyte count, with or without the samples ﬂagged for review removed (Table 2). A subset of the total number of samples (n = 46) were ﬂagged for cellular interference, caused by the presence of either giant PLTs, PLT clumping, or NRBCs. The DxH 800 showed again high correlative results with the LH 780 (r2 = 0.996) and FCM 2010 Blackwell Publishing Ltd, Int. Jnl. Lab. Hem. 2011, 33, 45–56 B. D. HEDLEY ET AL. DXH 800 PERFORMANCE EVALUATION 49 (b) LH 780 0.000 0.000 0.00 50.00 0.0 – – Upper limit DxH 800 400.000 8.500 255.0 150.00 3000.0 600.00 30.000 LH 780 400.00 8.000 250.0 200.00 3000.00 – –