Today's Veterinary Practice

JUL-AUG 2012

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Promotional Message from IDEXX Identifying inflammatory disease: get on the "band" wagon Why neutrophils? Neutrophils; specifically, mature segmented neutrophils, are the most common leukocyte in circulation in dogs and cats as well as in many other mammals. Mild-to-moderate elevations of segmented neutrophils are commonly encountered on complete blood counts performed on dogs and cats. Some of these patients are ill, whereas others are apparently healthy animals undergoing preventive or preanesthetic screening. Stress, excitement or inflammatory disease can all result in neutrophilia. Which of these is responsible? From a practitioner's perspective, this is a very important question that needs answering. Since neutrophils are involved in different types of physiologic and pathologic processes, the ability to accurately recognize them is extremely important. The complete five-part leukocyte differential and the pattern of the various leukocyte increases and decreases are also essential in defining the underlying cause of the neutrophilia. The more advanced hematology analyzers accurately determine these various leukocyte numbers. However, there is one additional cell type that is critical for more accurately diagnosing inflammatory disease: the immature neutrophil or "band." The band is an extremely uncommon leukocyte in the peripheral blood of the healthy animal, with typically less than 300 bands/µL present, but is considered the hallmark of inflammation when increased in numbers. Until very recently, reliable, automated identification of bands has been challenging even for reference laboratory analyzers and, to date, microscopic evaluation of a blood film was the ONLY way to identify the presence of bands. The detection of band neutrophils becomes a reality The recent capability of a point-of-care hematology analyzer to detect increased *%&99 -BCPSBUPSJFT *OD "MM SJHIUT SFTFSWFE t numbers of band neutrophils patient- side represents a major advancement in veterinary hematology for many important reasons. The vast majority of inflammatory conditions result in only minimal-to-mild increases in total neutrophil numbers. Even moderate neutrophilia due to inflammation cannot be differentiated from other common causes of neutrophilia, such as glucocorticoid influence (stress) Authors: W. Lee Barteaux, BS, DVM, MRCVS Peter K. Kintzer, DVM, DACVIM Dennis B. DeNicola, DVM, PhD, DACVP count (CBC), it is termed a "degenerative left shift." In addition to a left shift, morphologic abnormalities identified as "toxicity," including increased cytoplasmic basophilia and foaminess, are often seen with the presence of bands. Increased toxicity indicates more severe inflammation and a potential underlying bacterial etiology. The recent capability of an in-house hematology analyzer to detect increased numbers of band neutrophils patient-side represents a major advancement in veterinary hematology for many important reasons. and epinephrine influence (excitement). Stress itself can result in neutrophil counts as high as or even higher than 30,000/µL. Therefore, in most cases, an increased neutrophil count alone is difficult to accurately interpret and an increase in bands may be the only way to identify the presence and the severity of an inflammatory process. What are a left shift and toxicity? The number of bands in circulation, often termed a "left shift," provides information regarding the severity of the inflammatory process. The higher the number of bands, the more severe the left shift. For a very mild inflammatory process, the bone marrow can adequately handle the demand for neutrophils; however, with more severe inflammation, this pool of mature neutrophils can be exhausted and the less mature forms are forced into circulation. With extremely severe inflammatory processes, especially with bacterial-associated disease, not only bands but even earlier neutrophil precursors may be seen. When bands and earlier precursors outnumber the mature neutrophils on the complete blood This information has not been peer-reviewed and does not necessarily reflect the opinions of nor constitute or imply endorsement or recommendation by the Publisher or Editorial Board. The Publisher is not responsible for any data, opinions or statements provided herein. Ï All ®/TM marks are owned by IDEXX Laboratories, Inc. or its affiliates in the United States and/or other countries. The IDEXX Privacy Policy is available at idexx.com. Conclusion Both the identification and the characterization of a band neutrophil population in circulation is essential in properly interpreting leukocyte abnormalities; mere numbers of neutrophils are inadequate. It's important to understand that while the ability to detect the presence of band neutrophils patient-side represents a major advance in veterinary hematology, it does not replace the need to perform blood film evaluation. The presence of bands should reinforce the need to perform a blood film analysis and always warrants further investigation, including additional laboratory diagnostics and imaging studies. As stated previously, the detection of bands by the automated, point-of-care hematology analyzer will prevent many significant disease processes from being overlooked when the leukogram is otherwise unremarkable. So, don't miss the "band" wagon on inflammatory disease. For more information regarding patient-side detection of increased band neutrophils, go to idexx.com/hematology.

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