Comparison of Delta Total Nucleated Cells Assessed via Sysmex XT-2000iV and Sysmex XN-1000V in Effusions in Cats

The ratio of the nucleated cell counts (ΔTNC) provided by the Sysmex XT-2000iV DIFF and BASO channels has been proven to be useful in differentiating effusions in cats; in particular, a ΔTNC > 2.5 was found to have high accuracy for effusive FIP. The objective of this study was to compare the ΔTNC obtained with the Sysmex XT-2000iV and Sysmex XN-1000V on different types of effusions. Fresh effusions from cats were evaluated with both analyzers. WBC-BASO, WBC-DIFF, and ΔTNC-XT from the Sysmex XT-2000iV and TNC-WNR, TNC-WDF, and ΔTNC-XN from the Sysmex XN-1000V were recorded and compared. Forty-five feline effusions were collected. The results were not significantly different for all parameters evaluated. The Passing and Bablok regression analysis for ΔTNC-XT and ΔTNC-XN revealed a slope of 1.612 (95% CI 1.030 to 2.316) and an intercept of −0.744 (95% CI −1.591 to −0.120); the Bland–Altman difference plot showed a positive bias of 4.382 (p = 0.02). Despite the finding of a positive proportional and constant bias between ΔTNC-XT and ΔTNC-XN, evident especially at high ΔTNC values, samples were classified accordingly between the two analyzers when ΔTNC-XT cut-offs were used, allowing the same accuracy for the identification of suspected and compatible FIP samples.