Performance Evaluation of the Sysmex XN, XR, and DI-60 Body Fluid Applications for Leukocyte Differentiation

In response to the growing demand for automation in body fluid (BF) analysis, we evaluated the research four-part white blood cell (WBC) differentiation provided by the Sysmex XN and XR hematology analyzers (BF mode), as well as the Sysmex digital cell imaging analyzer DI-60 (CellaVision) BF application for microscopic analysis.

Cerebrospinal, pleural, peritoneal, and synovial fluid samples were analyzed. The four-part WBC differentiation (neutrophil, lymphocyte, monocyte, and eosinophil count (%)) provided by the XN- and XR-BF mode and the DI-60 BF application was compared to manual microscopic examination of May-Grünwald Giemsa stained cytocentrifuge slides. Additionally, the DI-60 BF application was assessed for its capability to detect malignancies.

A total of 205 BF samples were included in the evaluation of the four-part WBC differentiation of the XN- and XR-BF mode. A very strong correlation coefficient (r_s) between the XN/XR analyzer and manual microscopic examination was observed for neutrophils (%): 0.851 (XN); 0.862 (XR) and lymphocytes (%): 0.833 (XN); 0.842 (XR). The XN and XR analyzers reported lower monocyte counts compared to manual microscopic examination (bias = -3.21% (XN); -1.16% (XR)). The eosinophil count (%) showed suboptimal correlation between the automated analyzers and manual microscopy (r_s = 0.428 (XN); 0.555 (XR)), probably due to low levels and outliers. Out of 161 cytospin slides, 39 could not be processed by the DI-60, resulting in 122 remaining samples. All WBC types showed strong correlation between the manual count and the DI-60 count (r_s values of 0.735-0.974).

The four-part WBC differentiation provided by the Sysmex XN- and XR-BF mode and the Sysmex DI-60 BF application are valuable tools for automating and standardizing BF analysis.