Applications of flow cytometry in equine medicine: current clinical and research perspectives

Flow cytometry is a powerful analytical technique that enables rapid, quantitative, and multiparametric assessment of individual cells in suspension. Owing to its ability to evaluate cellular morphology, viability, and the expression of specific surface and intracellular markers, it has become an indispensable tool in biomedical research and clinical diagnostics. Over the past two decades, significant advances in cytometric technologies and the increasing availability of species-specific reagents have expanded the applicability of flow cytometry in equine medicine. This review highlights the predominantly research-based applications of flow cytometry in horses and their potential to address diagnostic gaps and complement conventional diagnostic methods. Particular attention is given to its principal applications in equine clinical immunology, including peripheral blood lymphocyte immunophenotyping; oncology, through the characterization of hematopoietic and lymphoid neoplasms; internal medicine, via cytometric evaluation of bronchoalveolar lavage fluid; and andrology, where flow cytometry serves as a valuable tool for the assessment of stallion semen quality. The article also highlights recent developments and discusses the growing role of flow cytometry as a diagnostic and research platform in contemporary equine medicine.