Utility of an automated analyzer for cytological analysis of bovine cerebrospinal fluid

Cerebrospinal fluid (CSF) cytological analysis is essential for diagnosing central nervous system (CNS) disorders in cattle, yet conventional methods rely on manual cell counting and microscopic evaluation, which can be time-consuming. Automated CSF analysis offers the potential for significantly faster results, a major advantage in emergency settings. In this study, we assessed the utility of a hematology analyzer (Procyte Dx®, IDEXX Laboratories) as a tool for CSF cytological analysis in cattle, aiming to support automated diagnosis of CNS disorders. A total of 131 cattle-24 healthy and 107 referred for neurological signs-were evaluated, with CSF samples analyzed in parallel using the automated analyzer and conventional laboratory methods within one hour of collection. The analyzer demonstrated good diagnostic performance for detecting CSF pleocytosis (AUC = 0.94), with a sensitivity of 97 % and specificity of 81 % at a total nucleated cell count (TNCC) cutoff of 20 cells/μL. This threshold is higher than the reported 10 cells/μL and may reflect both the analyzer's tendency to overestimate TNCC and its limited resolution at low cellularity, as it reports in increments of 10 cells/μL. Furthermore, the automated analyzer demonstrated limitations in performing differential cell counts on samples with TNCC ≤ 1000 cells/μL. While automated CSF analysis proved rapid and effective in identifying moderate to severe pleocytosis, software improvements are needed to enhance the accuracy of differential cell counts and to ensure reliable TNCC estimation in cases of mild pleocytosis. Nonetheless, it can serve as a valuable tool in emergency settings when cytological evaluation is unavailable.