Evaluation of a Manual Cytocentrifuge versus the Standard Automated Cytocentrifuge in the Analysis of Canine Cerebrospinal Fluid: A Case Series of 55 Dogs

SIMPLE SUMMARY: Veterinary cytology has become a cornerstone method for confirming initial clinical diagnosis, guiding early owner communication and therapeutic planning. Cytology is often acclaimed for the ease of obtaining samples, quick results and lower cost when compared with other diagnostic tests. The analysis of cerebrospinal fluid plays a central role in the management of neurologic patients. Cerebrospinal fluid is typically a low-protein, low-cell fluid that must be rapidly cytocentrifuged to obtain a good-quality cytologic slide, called a cytospin. Automated cytocentrifuges are relatively expensive pieces of equipment typically only available in veterinary and human diagnostic laboratories, but are not usually available for use in routine clinical practice. A low-cost manual cytocentrifuge is readily available and has been developed to obtain in-clinic cytospins of a variety of fluid samples. In this study, the use of a manual cytocentrifuge was validated for analysis of canine cerebrospinal fluids in routine clinical practice. ABSTRACT: Cytospins are important for evaluating fluids with very low cellularity such as cerebrospinal fluid (CSF). The aim of this study was to compare the CSF cytospin preparations obtained from automated and manual cytocentrifugation methods. A prospective case series was performed to analyze canine CSF samples using both centrifugation methods. The cytospins were processed within 30–60 min and prepared simultaneously in a conventional automated cytocentrifuge and in an in-house manual cytocentrifuge, using a fixed volume of CSF fluid. The cellularity, differential cell count and the proportion of cell artifacts (pseudopods and vacuolization) were blindly assessed in the cytospin preparations obtained using the two methods. The agreement and correlation between both methods were analyzed. There were 55 dogs enrolled (48 prospectively and 7 retrospectively) in the study. 38 dogs had normal total nucleated cell counts, while 17 had pleocytosis. Automated and manual cytocentrifugation had similar cell yields, and no significant differences in differential cell counts or the presence of artifacts existed between both methods. In cases with pleocytosis, the cytologic diagnosis obtained using each method was similar. Manual cytocentrifugation of CSF is a reliable and economic method designed for routine clinical practice. Its use reduces the specimen deterioration related to processing and analysis delays when samples are transported to external laboratories for evaluation.