"With LaserCyte's expanded differential and WBC range, we can work up cases faster to determine appropriate treatment or further diagnostics."

James F. Young, DVM
Hospital Director
Atlantic Street Veterinary Hospital and
Pet Emergency Center, Inc., Roseville, CA

Case study
Seven-year-old, intact domestic longhair male cat named Whiskers.

History
Whiskers has a recent history of anorexia and decreased activity evidenced in his unwillingness to play as usual.

Physical examination
Whiskers is in good body condition and has a good body weight. There is a high-normal body temperature and a slight increased respiratory rate. Increased and slightly harsh lung sounds are heard during auscultation of the lung field. Whiskers is calm during the examination and during blood collection, and appears quite bright and alert.

Comment on LaserCyte® report
Differential algorithm issues. Confirm with blood smear.

LaserCyte data description

Leukon—There is a mild leukocytosis characterized by a neutrophilia and an eosinophilia with a slight monocytosis, slight basophilia and a normal lymphocyte count.

Erythron—No significant abnormalities are noted.

Thrombon—Platelet numbers are within reference-range limits. Few enlarged platelet forms are present, but this is an equivocal finding in the peripheral blood film of a cat.

LaserCyte Complete Blood Count:

Blood film review—A rapid microscopic review of the blood film in less than two minutes quickly confirms the numerical data generated by the LaserCyte analyzer. Distribution of the leukocytes appears even, there are primarily neutrophils mixed with easily found eosinophils (Figure 1), and slightly fewer relative numbers of monocytes and lymphocytes. The various leukocytes are morphologically normal.

Interpretation of LaserCyte data
The leukocyte changes indicate the presence of an inflammatory condition based upon the finding of a neutrophilia, eosinophilia, monocytosis and basophilia in the face of a normal lymphocyte count. The normal lymphocyte count in a non-excited cat suggests no significant ongoing glucocorticoid influence (stress). If lymphopenia was evident also, the neutrophilia and potential monocytosis could have been attributed to the stress itself. The eosinophilia suggests a relatively specific group of inflammatory conditions, including parasitic infections, fleabite dermatitis, hypersensitivity or allergic conditions, as well as some less common disease process associated with eosinophilia, including neoplastic conditions such as mast cell tumor and occasionally malignant lymphoma. The identification of the eosinophilia is relatively critical in this case to assure correct selection of the next diagnostic procedures to further characterize Whiskers' disease.

How would other hematology analyzers perform?

Reference Laboratory—Most veterinary reference laboratories would have given similar results as the LaserCyte. With either of the instruments that are currently used by most laboratories or with a manual leukocyte differential count, the significant eosinophilia would have been recognized.

QBC® VetAutoread™—Since this instrument does not have the ability to identify feline eosinophils or separate lymphocytes and monocytes, several critical components of the leukocytosis would be missed. Only a granulocytosis would have been recognized, and since the majority of our feline granulocytoses are neutrophilias without eosinophilia, an incorrect interpretation would have been made unless a manual leukocyte differential were performed on a blood film.

Impedance Counters—Similar to the QBC VetAutoread, impedance counters do not have the ability to distinguish different types of granulocytes (neutrophils, eosinophils and basophils are all counted together as granulocytes). Again, the most critical abnormality present in Whiskers' CBC, eosinophilia, would have been missed unless a manual leukocyte differential were performed on a blood film.

Case outcome
Because of the physical findings of increased and abnormal respiratory sounds during auscultation, primary respiratory disease was investigated. A simple transtracheal wash was performed and many eosinophils with no identifiable infectious etiologic agent were found, indicating that the respiratory tract was the likely primary site of inflammation. This finding in combination with the radiographic findings of increased interstitial pattern is supportive of pulmonary eosinophilic infiltrative disease, suggestive of feline asthma. This was the clinical diagnosis and Whiskers responded to appropriate therapy.

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Announcing LaserCyte® Equine Capability

The LaserCyte® Hematology Analyzer now offers equine veterinarians a COMPLETE blood count, allowing for a truly comprehensive CBC with complete indices, including red blood cell count, platelets and a 5-part white blood cell differential for equine patients. Now it's possible to get a truly complete insight into the health status of your equine patients within minutes.

LaserCyte uses proprietary laser-flow cytometry technology. Laser-flow cytometry is considered the "gold standard" by clinical pathologists because blood cells are aligned in a single file, allowing for a cell-by-cell laser interrogation that provides detailed analytical information. The absolute 5-part differential delivered by LaserCyte provides parameters necessary to distinguish between bacterial, viral and parasitic infections; inflammation; and allergic reactions.

The new LaserCyte equine panel is the latest offering in IDEXX's commitment to providing equine practitioners with diagnostic, treatment and information management support. IDEXX offers a broad and growing range of products and services that provide valuable information and decision support in the detection and management of equine diseases, including:

Pharmaceuticals
Hit hard and hit fast against equine protozoal myeloencephalitis (EPM) with Navigator (32% Nitazoxanide) Antiprotozoal Oral Paste. It works by killing the EPM parasite after just 28 days of treatment. Learn about this neurological disease and our new treatment, and download our neurological examination form. (10 KB)

Digital Imaging
Computed Radiography: With the IDEXX-CR™ computed radiography system it's possible to radiograph, diagnose and treat patients in the field—it's the first affordable, mobile digital imaging system customized for veterinarians.

In-House Analyzers
IDEXX VetLab® System: Get fast answers and a complete health picture with in-house analyzers for blood chemistries, electrolytes and hematology. All results are combined on a single report to assist with diagnoses and client education.

In-House Tests
SNAP® Foal IgG Test: Read neonatal IgG levels in just seven minutes with our new foal-side diagnostic kit. Equine Infectious Anemia (EIA) Tests: IDEXX offers USDA-licensed assays in two formats for use by certified laboratories to detect this equine disease.

Reference Laboratories
IDEXX Reference Laboratories: Our network of reference laboratories provides comprehensive clinical testing services and access to equine and other consulting specialists for diagnostic and treatment support for your difficult cases.

Telemedicine
IDEXX Telemedicine: Receive rapid consultation from board-certified specialists, including cardiologists, radiologists and internists.

Computer Systems
IDEXX Cornerstone®: Build client compliance, enhance your medical care and staff efficiencies, and increase revenue with our innovative practice management information system.

For more information on LaserCyte call 1-800-340-4579 or e-mail diagnosticedge@idexx.com.

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2004 American Animal Hospital Association Annual Meeting, Tampa, Florida
Saturday, March 20, Tampa Marriott Waterside Hotel and Marina

Lunch will be provided at the above session. To register, send us an e-mail with your name, practice, clinic address and how best to contact you. We will send you more specific location information. Seating is limited, so sign up early!

More IDEXX-featured talks at AAHA. (29 KB)

Columbus, Ohio
Tuesday, April 27, Buckeye Hall of Fame Café, 1421 Olentangy River Road

To register, call 1-800-551-0998 ext. 4118 or send us an e-mail.

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For the month of March—submit a hematology question for our clinical pathologists to answer in an upcoming issue of Diagnostic Edge and receive a prize (an IDEXX Laboratories Guide to Hematology, a stainless steel IDEXX travel mug, T-shirt, or other comparable prize to be determined by IDEXX Laboratories).

This month's question is: A significant number of CBC results that I get back from IDEXX Reference Laboratories contain the comment "reactive lymphocytes noted." I am trying to encourage one of my veterinary technicians to perform blood films routinely on our in-house hematology analyses. How do I recognize these "reactive lymphocytes" and what is the significance of finding them in circulation?

Responding to this month's question is Dennis B. DeNicola, DVM, PhD, DACVP, Chief Veterinary Educator, IDEXX Laboratories.

Reactive lymphocytes are relatively common and their presence in circulation is not "normal;" however, they rarely provide specific information. The presence of reactive lymphocytes indicates systemic antigenic stimulation. This stimulation can be from recent immunization, or exposure to infectious agents or to a variety of non-infectious processes, including neoplastic disease and inflammation associated with foreign bodies.

There are a variety of morphologic changes associated with "reactivity" of lymphocytes. The predominating normal small lymphocyte (Figure 1) is a mononuclear cell approximately 9–11 micrometers in diameter mononuclear cell with a very high nuclear/cytoplasmic ratio and a generally round to slightly indented nucleus with dense and often smudged nuclear chromatin. The most common features of "reactivity" include the finding of a more deeply blue-staining cytoplasm and a mild increase in the amount of cytoplasm (Figure 2). With marked reactivity, the amount of deeply staining cytoplasm can be significantly increased and, in some cases, a plasmacytoid appearance with a visible perinuclear clear zone in the cytoplasm can be seen (Figure 3). Nuclear morphology may take on a more clefted or irregular shape compared to the typical round to slightly indented nucleus of the normal or typical reactive lymphocyte (Figure 4).

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A blood film is an important complement to an automated CBC. Follow these easy steps to prepare a high-quality blood film.

For specimens with low hematocrits (anemia), increase the angle between the slides to make a thicker blood smear.

For specimens with high hematocrits (dehydration, polycythemia, etc.), decrease the angle between the slides to make a thinner blood smear.

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... and we want you to hear from us! Pass the following link along to your friends and colleagues. They can register for the Diagnostic Edge to learn more about hematology, stay informed of the latest IDEXX hematology products and services, and respond to various customer and market surveys that we will soon offer. Registration is easy at www.idexx.com/diagnosticedge.

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