Comparison of Cerebrospinal Fluid Cellular Analysis by Optical Microscopy and Sysmex XN 9000

Background: This study was designed to compare the body fluid module of Sysmex XN9000 (XN-BF) with optical microscopy (OM) for cerebrospinal fluid (CSF) analysis after two-step cell slide centrifuge (TSCSC), defining the best procedure for CSF optical microscopy analysis. Methods: Items of RBC, WBC enumeration and differentiation were observed. The cell count and morphologic evaluation of the cellular composition by OM was carried out both with and without two-step cell slide centrifuge (TSCSC) and were compared the data with XN-BF. Results: There were 69.98 +/- 4.94 RBC and 36.98 +/- 3.39 WBC in one OSCSC microscopic field whereas there were 96.35 +/- 5.41 RBC and 66.15 +/- 4.85 WBC in one TSCSC microscopic field in the same sample (*200). There was a statistical difference between those two methods (p = 0.000). Excellent correlation was found between total cell count with both OM and XN-BF. The R2 value for RBC and WBC counts were 0.99 and 0.96, respectively. For WBC differential, the R2 values were 0.98 for PMN and 0.70 for MN. Correlation of MN was poorer than PMN. As far as the tumor cell, phagocyte, and plasma cell with high fluorescence were concerned, OM were not consistent with XN-BF. Conclusions: The TSCSC procedure contributes to the separation of cells and other ingredients. XN-BF displays excellent performance at RBC and WBC cell count except for mononuclear cells, tumor cells, phagocytes, and leukemia cells. which makes it just a practical alternative to total cell (WBC, RBC) count for CSF samples. Detailed morphologic workup of CSF samples is mandated in all cases with meningoencephalitis, elevated cell count, sub-arachnoid hemorrhage and meningeal carcinomatosis, the TSCSC procedure is recommended. (Clin. Lab. 2023;69:2274-2279. DOI: 10.7754/Clin.Lab.2023.230403)