Automatic microscopic count and characterization of cerebrospinal fluid cells: an alternative to standardized analysis

Abstract Objectives Cerebrospinal fluid (CSF) analysis is important for the diagnosis and follow-up of central nervous system diseases. In this study, we propose a cellular analysis of CSF by digital optical microscopy (OM) using a semi-automatic instrument (SediMAX Lite, Menarini Diagnostic) that evaluates cells and produces digital images. Methods A total of 110 CSF samples were analyzed (70 from the General Laboratory of the Careggi University Hospital in Florence and 40 from the Clinical-Chemical Analysis Laboratory of the San Donato Hospital in Arezzo). Manual OM cell counts were performed in a manual OM counting chamber. For semi-automatic cell counting, the SediMAX Lite was used, which captured 15 digital images for each sample (treated and untreated with Turk staining), stored in the instrument database. Method comparison and instrument evaluation were performed. Results The agreement between the OM manual and SediMAX Lite for RBC showed a kappa=0.80, while for WBC count was kappa=0.86. The Passing-Bablok regression slope, in the comparison of WBC counts between the two methods in samples non-pretreated with Türk’s fluid, was 0.94 (95 % CI 0.86 to 1.00) and intercept was 1.00 (95 % CI, 0.00–1.00). The Bland-Altman bias was 4.39 cells/µL (95 % CI, −4.27 to 13.05), lower limit bias was −82.89 cells/µL (95 % CI, −97.89 to −67.89) and upper limit was 91.68 cells/µL (95 % CI, 76.68 to 106.68). Comparison of WBC counts between the two methods in samples pretreated with Türk’s fluid showed at the Passing-Bablok regression slope was 1.29 (95 % CI 1.16 to 1.44) and intercept was 1.00 (95 % CI, 0.56–1.00). The Bland-Altman bias was −22.12 cells/µL (95 % CI, −36.92 to −7.32), lower limit bias was −171.24 cells/µL (95 % CI, −196.87 to −145.61) and upper limit was 127.00 cells/µL (95 % CI, 101.38 to 152.63). Conclusions SediMAX Lite shows quantitative agreement is limited, particularly in low cellularity samples. The system may serve as a supportive tool for standardized digital imaging and qualitative identification of pleocytosis in laboratories requiring continuous availability.