Cytological analysis of equine bronchoalveolar lavage fluid. Part 2: Comparison of smear and cytocentrifuged preparations.

The researchers have devised a more convenient method for veterinarians to analyze horse lung fluid samples, comparing this novel smear method to the traditional laboratory cytocentrifuged method. Despite observing smaller and darker cells, the smear method proved reliable for diagnosing equine lung diseases associated with neutrophils.

Study Objective and Methodology

• The primary aim of this study was to formulate a practical and diagnostically effective smear method for preparing equine bronchoalveolar lavage fluid (BALF) samples. The method aimed to be handy and convenient for on-field practitioners.
• The researchers created a smear method where they added serum to the equine BALF samples. They then compared the results with those obtained from standard laboratory cytocentrifuged preparations, specifically focusing on aspects like cell morphology, differential cell counts (DCC), and repeatability of counting DCC.
• The team collected BALF samples from five control horses and five horses susceptible to ‘heaves,’ a chronic inflammatory condition affecting the lungs.

Findings of the Study

• The smear preparations of BALF produced smaller, darker staining cells, causing some challenges in cytological identification as compared to cytocentrifuged preparations.
• On comparing the two methods, the cytocentrifuged preparations presented a significantly higher macrophage DCC and a lower lymphocyte DCC than the smear preparations.
• Additionally, mast cell and eosinophil DCC were observed to be significantly higher on cytocentrifuged preparations than on smear preparations of BALF.

Conclusion and Implications

• Despite some of the mentioned shortcomings, smear preparations proved to be reliable for the cytological diagnosis of equine neutrophilic pulmonary disease which is a subset of equine lung diseases.
• This smear method offers a low resource and time-saving alternative to traditional practices where samples had to be sent to a lab for processing and cytological analysis.
• The results of this research not only provide a novel approach to field veterinarians but also a useful tool in timely diagnosing and treating equine lung conditions.