Analytical Performance of the Sysmex XF-1600 Flow Cytometer in Routine Clinical Practice

Flow cytometry systems are increasingly used for the identification and quantification of lymphocyte subpopulations, supporting the diagnosis and monitoring of hematological and immunological conditions. This study aimed to evaluate the analytical performance of the novel Sysmex XF-1600 flow cytometer for lymphocyte subpopulation quantification in peripheral blood, including precision, carryover, and agreement with established laboratory methods.

Peripheral blood samples from routine clinical workload were analysed in the hematology laboratory. Analytical performance was assessed by evaluating precision (repeatability and reproducibility) and carryover. Absolute lymphocyte and leukocyte counts obtained using the XF-1600 automated sample preparation and volumetric counting system were compared with the Sysmex XN-series hematology analyser, while lymphocyte subset quantification was compared with the Navios flow cytometer (Beckman Coulter).

The XF-1600 showed coefficients of variation below 6% for major lymphocyte populations, including CD3+, CD4+, CD8+, CD19+, and CD16+/CD56+ cells. No carryover was detected. Comparison with the Sysmex XN analyser showed strong correlation for leukocyte and lymphocyte counts (Spearman's ρ = 0.986 and 0.993, respectively). Comparison with the Navios flow cytometer demonstrated high correlation across lymphocyte subpopulations (Spearman's ρ > 0.9 for most parameters). Bland-Altman and Passing-Bablok analyses showed good agreement between methods, although some parameters were not fully interchangeable.

The Sysmex XF-1600 flow cytometer demonstrated good analytical performance for lymphocyte subset quantification, with high precision and strong agreement with routinely used laboratory methods. The integration of automated sample preparation and volumetric counting may support standardization of immunophenotyping workflows in clinical laboratories.