Application of flow cytometric techniques to veterinary clinical hematology

Flow cytometry has emerged as a major new technology in veterinary clinical laboratories. Flow cytometers in current use include stand-alone instruments and cytometers incorporated into hematology analyzers. Flow cytometers offer rapid and quantitative analysis of a variety of cell types based on cell size, molecular complexity, and antigenic composition. Therefore, flow cytometry complements and extends knowledge that can be obtained by light microscopy. Stand-alone instruments are very flexible, however, this flexibility opens the instrument to obtaining invalid or misleading results. The recent development of monoclonal antibodies specific for epitopes on blood cells of food and companion animals has greatly expanded the spectrum of tests with potential clinical application. Tests that appear to have the greatest potential for routine application include reticulocyte and reticulated platelet enumeration, detection of erythrocyte-bound immunoglobulin, immunophenotyping of leukemias and lymphomas, and bone marrow differential cell counting. This report will briefly review the technical aspects of flow cytometry and then focus on techniques with present or potential application to the veterinary clinical laboratory.