Equine Tracheobronchial Wash Filtration and Its Effects on Differential Cell Count

Abstract

Tracheobronchial wash (TBW) is a method to recover cell samples from the airways. The cytology of TBW fluid is an important technique for the diagnosis of pulmonary diseases in horses. Excessive mucus in TBW may cause cell damage and morphological changes that hinder cell type recognition, resulting in a misdiagnosis. The aim of this study was to compare the results of differential cell count in a tracheobronchial wash of filtered and non-filtered samples. Endoscopy and TBW procedures were performed in thirty horses. Each TBW sample was split into two aliquots. Two groups were formed: non-filtrated aliquots (NF) and filtrated aliquots (F). The filtration was performed using a hydrophilic gauze pad. After centrifugation, the differential cell count was performed considering 300 nucleated cells. The filtrated aliquots results presented a significant increase of macrophages count and a significant decrease in neutrophils count comparing to the results of non-filtrated aliquots. These findings were consistent with results of filtered bronchoalveolar wash published studies. Therefore, the filtration of TBW is not an efficient method.