Evaluation of the fully automated hematological analyzer Sysmex XE-5000 for flow cytometric analysis of peritoneal fluid.

Although microscopy still represents the gold standard for cytometric analysis of peritoneal fluids, automated flow cytometry may improve throughput and accuracy. We evaluated the performance of total nucleated cell (TNC), white blood cell (WBC), polymorphonuclear cell (PMN), and mononuclear cell (MONO) counts of Sysmex XE-5000 on peritoneal fluids. The imprecision was excellent, being always lower than 11%, whereas linearity studies yielded correlation coefficients of 1.00 for all parameters. The carryover was always lower than 0.2%. The comparison between XE-5000 and microscopic analysis of 117 ascitic fluids yielded correlation coefficients always greater than 0.96, with mean biases <11/µL. The diagnostic accuracy versus manual microscopy was greater than that of XE-2100, especially at thresholds for septic ascites (100 versus 98% for ≥500 WBC/µL; 98 versus 93% for ≥250 PMN/µL). The correlation with manual microscopy for macrophages and mesothelial cell count was also higher for XE-5000 than for XE-2100 (0.63 versus 0.55). The results of this evaluation show optimal performance of XE-5000 for routine analysis of ascitic fluids, which are combined with the advantages of automated analysis such as high throughout, shortened turnaround time, no need of sample preparation and trained staff, reduced sample volume, and less likelihood of transcriptional errors.