Evaluation of the <scp>IDEXX</scp> Procyte Dx Analyzer for the Measurement of Total and Differential Cellular Counts of Bronchoalveolar Lavage Fluid in Healthy Beagles and Dogs with Lower Respiratory Tract Diseases

BACKGROUND: Bronchoalveolar lavage fluid (BALF) analysis is a key diagnostic tool in veterinary respiratory medicine. The IDEXX ProCyte Dx analyzer was developed for blood formulation and cellular counting in various fluids, but its applicability for BALF analysis remains unexplored. OBJECTIVES: To assess the agreement between manual counting and automated counting using the IDEXX ProCyte Dx analyzer for total cell count (TCC) and differential cell count (DCC) in BALF samples from healthy and diseased dogs, under two pretreatment conditions: mucolytic treatment with dithiothreitol (DTT) or filtration. METHODS: BALF from 10 healthy beagles and 14 diseased dogs were analyzed to compare TCC and DCC between manual and automated methods across pretreatment conditions. RESULTS: In healthy dogs, Bland-Altman analysis on log-transformed data demonstrated a mean ratio close to 1 and acceptable 95% limits of agreement between manual and automated methods and between pretreatment conditions. In diseased dogs, good agreement was observed between manual and automated methods for filtered samples only; the other comparisons showed poor agreement. In both healthy and diseased dogs, Passing-Bablok regression analysis did not detect systematic or proportional bias between methods. Automated DCC was inconsistent compared with manual methods in both healthy and diseased dogs. CONCLUSIONS: The IDEXX ProCyte Dx analyzer can be used for TCC measurement of pre-treated BALF samples in healthy dogs. In diseased dogs, filtration is preferred over DTT-treatment for automated counting, and results should be interpreted with caution due to the unpredictable influence of pretreatment on cellular counts. For DCC, automated methods are unreliable.