Evaluation of the Idexx Procyte Dx® for analysis of canine cerebrospinal fluid

OBJECTIVES: To assess the utility of the Idexx ProCyte Dx(R) haematology analyser for assessing total nucleated cell count and differential cell counts in canine cerebrospinal fluid. MATERIALS AND METHODS: Seventy-three client-owned dogs undergoing investigations for pyrexia and/or neurological signs were prospectively included. Cerebrospinal fluid samples were assessed using an Idexx ProCyte Dx(R) analyser and the results were compared to those obtained with the external laboratory reference standard. RESULTS: The Idexx ProCyte Dx(R) performed with good sensitivity (92.6%) and moderate specificity (67.4%) for total nucleated cell count when compared to the reference standard. Qualitative assessment of the Idexx ProCyte Dx(R) scatter plots, and quantitative assessment of differential cell counts where available, appeared to correlate well with the external laboratory manual differential cell counts, with a good-to-high agreement in 25 of 26 samples (96.2%). CLINICAL SIGNIFICANCE: The Idexx ProCyte Dx(R) analyser performed well in determining the total nucleated cell count and differential cell counts in canine cerebrospinal fluid when compared to a reference standard of external laboratory analysis, except for cell counts higher than ~1000/muL. As the Idexx ProCyte Dx(R) currently only provides a cell count in 10 cells/muL increments, software modification may improve agreement between the two methods. As in human medicine, automated methods may prove useful in the future for cerebrospinal fluid analysis in addition to manual assessment, particularly in an emergency setting.