"We don't send out any CBCs. We use our LaserCyte® machine 24 hours a day to support this clinic and our two outside clinics, because the more we do in-house, the better it is for our patients. I have 100% confidence in this instrument—the speed, the accuracy and the great maintenance."

Jack Austen, PhD
Metairie Small Animal Hospital
Metairie, LA

Visit IDEXX representatives at NAVC to learn about the introduction of the Urine P:C Ratio
Event:	The North American Veterinary Conference
When:	January 8–12, 2005
Where:	Orlando, Florida
Booth:	2111

Featured Case Study: Hemolytic Anemia in a Cat

Signalment: Two-year-old, intact female, domestic shorthair cat named Tiffany

Clinical Presentation: Tiffany presented with a sudden onset of depression and anorexia. A mild heart murmur, difficult to characterize during auscultation, was detected, but beyond the relatively severe depression, no obvious physical abnormalities were noted.

In-House Laboratory Findings

Initial CBC Data Assessment:

Red Blood Cells—There was a moderately severe, normocytic and normochromic anemia of unidentified etiology. The potential of an inappropriate nucleated red blood cell response associated with bone marrow stromal damage was strongly considered since there was no morphologic support for strong regenerative anemia (normal MCV and MCHC) that would justify the degree of nucleated red blood cell response.

White Blood Cells—There was a mild leukocytosis characterized by a mature neutrophilia, monocytosis and a basophilia. Changes were most consistent with an inflammatory process associated with a peripheral demand for macrophages (monocytosis).

Platelets—were too clumped to allow accurate enumeration.

Complete Blood Count Results

CBC Data Assessment in Conjunction with a Peripheral Blood-Film Review
(Visit the March 2004 Diagnostic Edge for tips on creating a high-quality blood smear)

Figure 1. Figure 2.

The presence of high numbers of nucleated red blood cells was also confirmed; the degree of polychromasia was much greater than the degree of metarubricytosis, suggesting that primary bone marrow stromal damage was not the cause for the nucleated red blood cell response.

White Blood Cells—Leukocyte distribution as reported in the CBC was validated. No significant leukocyte morphologic abnormalities were noted.

Platelets—Figure 1 and Figure 2 show platelets appearing adequate in number, but as mentioned in the initial data presentation, an accurate enumeration of platelets was not possible because of platelet clumping. Enlarged platelet forms were present, but this is an equivocal finding in the peripheral blood of cats. It may be associated with accelerated thrombopoiesis at the marrow level in response to a peripheral demand for platelets.

Clinical Outcome:

Tiffany was treated with both antibiotic therapy specifically directed against Mycoplasma haemofelis, and immunosuppression to specifically address the probable immune-mediated component to the anemia. Tiffany's clinical condition worsened and the owners elected for euthanasia.

Significant Points Related to This Case:

An absolute reticulocyte count and peripheral blood-film evaluation identifying the marked polychromasia, which correlates with the reticulocyte count, was essential in properly characterizing this anemia as strongly regenerative and; therefore, probably hemolytic in origin. The lack of an increased MCV and a decreased MCHC, which is commonly seen with regenerative anemia, could be misleading if interpreted without the reticulocyte count or blood-film evaluation. Many strongly regenerative anemias, or cases where there is a significant reticulocytosis for other reasons, will have high or low normal MCV and MCHC values, respectively, or will actually have MCV and MCHC values outside of the reference range. The presence of significant numbers of reticulocytes in circulation forces these values in their respective directions because these immature red blood cell forms are larger than mature red blood cells and have less hemoglobin content. The primary problem with using these parameters as the sole method of differentiating regenerative from nonregenerative anemia is that they only represent the "mean" cell volume and cell hemoglobin concentration. There may be an adequate reticulocyte response to justify calling an anemia regenerative even though the "mean" of all the circulating erythrocytes does not change enough to bring the values out of the reference range. In addition, there are clinical situations where increased MCV (myelodysplasia) and decreased MCHC (developing iron deficiency) may be seen when there is no evidence of a "regenerative" picture.

The reticulocyte count is considered the most objective and reliable measure of bone marrow responsiveness to accurately classify anemia as to its regenerative status. An added advantage of the IDEXX LaserCyte® Hematology Analyzer profile is that an absolute reticulocyte count is provided with each canine and feline CBC. This valuable information is immediately available to the veterinarian, allowing him/her to answer the first and most important question when an anemia is identified, "is it a regenerative or nonregenerative?"

The suggestion of agglutination on the blood smear provides additional information leading to a logical interpretation that an immune-mediated component to this regenerative anemia may be present. Additional testing, including performing a saline agglutination test and possible Coombs test, would have been required to confirm this suspicion.

Because of the high number of nucleated red blood cells present in this case (204/100 WBC), an accurate instrument leukocyte count would have been impossible with a simple impedance-based hematology analyzer. The nucleated red blood cells would have been enumerated as other nucleated cells, giving a dramatically high false value for the leukocyte count if used without blood-film evaluation and correction for the nucleated red blood cells. The more advanced hematology analyzers utilize other methods such a laser-flow cytometry or enzyme cytochemistry to avoid this limitation. Because of the laser-flow cytometry methodology utilized by LaserCyte and the more advanced reference laboratory analyzers, the greater detailed interrogation of cellular elements allows easy differentiation between nucleated red blood cells and leukocytes. An accurate leukocyte count is possible without additional technical time to "correct" for the nucleated red blood cells whenever they are present.

Submit a Case Study

The recommendations contained in Diagnostic Edge educational materials are intended to provide general guidance only. As with any diagnosis or treatment, you should use clinical discretion with each patient based on a complete evaluation of the patient, including physical presentation and complete laboratory data. With respect to any drug therapy or monitoring program, you should refer to product inserts for a complete description of dosages, indications, interactions and cautions.

This summary was written by Dr. Dennis B. DeNicola of IDEXX Laboratories.

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Early detection of renal disease is now possible on the IDEXX VetTest® Chemistry Analyzer

By the time azotemia is discovered in blood chemistries and renal disease is diagnosed, up to 75% of an animal's kidneys may already be destroyed. While knowing an animal has kidney disease allows you to treat and manage the disease progression, having this knowledge before your patient develops azotemia can be far more advantageous.

For years, researchers have looked for ways to better predict kidney disease. Even small amounts of protein in the urine can be abnormal, and recent research shows that persistent high urine protein:creatinine (UPC) ratios are linked to a poor prognosis in patients.¹ The ability to quantify the level of proteinuria in an animal's urine is being recognized as a key tool to helping diagnose and monitor early renal disease.

This is now possible in your clinic with the IDEXX Urine P:C Ratio the first fully quantitative measure of urinary protein loss in-house. This convenient, fast and inexpensive new test for the VetTest® Chemistry Analyzer allows you to diagnose early renal disease, monitor and evaluate treatment, and alter the course of disease to enhance the lives of your patients.

Special Offer for Our Urine P:C Ratio Users

Sample prep kit includes:

• 50 pipette tips
• Two pipettors (one 10-µL, one 200-µL)
• One bottle of solution

Contact your IDEXX distributor for the availability of this special offer.

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Education and Events
We offer a variety of seminars and teleconferences about emerging trends and best practices in veterinary diagnostics—in a forum designed to involve, educate and motivate you and your staff.

• Visit the seminar and teleconference calendar and click the date to view the details.
• Fill out and submit the form to register.

LaserCyte® Analyzer User Group Session
Become a LaserCyte "super user" in just one afternoon!

Friday, January 7, 2005, 1:00 p.m. to 5:00 p.m.
Marriot World Center
8701 World Center Drive
Orlando, Florida

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Spotting Giardia—infected dogs and cats in-clinic

Giardia is a common intestinal parasite of dogs and cats. Infection prevalence can vary to more than 50%, depending on the population, and up to 100% in shelters and kennels.

Unfortunately, Giardia infection is commonly undiagnosed in the clinical setting. Why? One reason is methodology. Clinics have depended on microscopic evaluation of feces to identify Giardia trophozoites or cysts. Technicians know that the fecal float can be used to identify many internal parasites (i.e., roundworms and hookworms), and most parasites are readily identified by any number of in-house diagnostic microscopic methods. Giardia, on the other hand, is almost impossible to diagnose using disposable floatation kits.

Why is the microscopic identification of Giardia sometimes so difficult?

Three reasons.

1. It is difficult to identify Giardia because, unlike other parasites' eggs, the Giardia cysts are very delicate and are often damaged beyond recognition during preparation of the slide.

2. If you're not accustomed to identifying the tiny cysts, you can overlook them or confuse them with pollen, yeast and many other artifacts.

3. The trophozoites and cysts only shed intermittently, which means several fecal examinations may be necessary over several days for an accurate result.

Until now, veterinary technicians have depended on two in-house diagnostic techniques for identifying Giardia:

In 2004, IDEXX developed the SNAP® Giardia Test on the ELISA platform because of the many problems associated with current methods of diagnosing Giardia.

Detecting Giardia Infection:
A Comparison of In-House Microscopy Method vs. Reference Laboratory Methods

In a recent study, 617 fecal samples were tested for Giardia in the normal course of clinical practice.¹ Results from fecal floatation or fecal smears were recorded, and the samples were then forwarded for further reference testing. The results indicated poor performance of current in-house microscopy testing compared to ELISA and DIFM reference methods.

The SNAP Giardia Test provides many advantages for your practice.

• Easy to set up and run so you can test for Giardia while screening for other fecal parasites
• Only one sample is required, compared to three for microscopy—making your workflow much faster and easier
• Includes a unique conjugate-fecal swab that allows for much easier, "hands-off" sampling
• Fast results (just 8 minutes) so you can identify infected patients during their visits

When should you run a SNAP Giardia Test?

• Symptomatic animals (i.e., diarrhea, weight loss, etc.)—Anytime you run a fecal float on an animal you suspect has internal parasites, or a sick animal with semi-formed or liquid feces
• Animals at risk—Animals from shelters and kennels; animals that board frequently, visit doggie-daycare, or that go hiking and camping
• Confirming Giardia findings on asymptomatic patients—the SNAP Giardia Test can confirm suspect Giardia findings on healthy-pet fecal-float screens

How do you implement the SNAP Giardia Test into your practice?

• First, have a staff meeting to notify everyone of the protocol change, and then place a reminder to run the test near the slides and coverslips or microscope.
• Run the SNAP test during the fecal float; all results will be completed together.
• Change your invoice receipt or computer to include a comprehensive fecal charge.

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Calling All Qualified Urine Protein:Creatinine/Renal Disease Case Studies

Do you have a case study in which a urine protein:creatinine ratio helped you detect renal disease? If so, you could win a copy of Renal Disease in Dogs and Cats by Dr. Jonathan Elliott and Dr. Scott Brown, just for sending us a qualified submission!

The case that best exemplifies how clinics can "practice what's possible" will be featured in a special edition case study booklet on renal disease and proteinuria.

Qualified submissions must include:^*

• The patient's name, signalment, history, physical examination, bloodwork and a complete urinalysis (including an IDEXX Urine P:C Ratio result)
• A diagnosis of renal disease (either primary or secondary)
• The name, address and telephone number of your clinic; and the names of your veterinarians and veterinary technicians
• Pictures, if possible

^*Limit one case per clinic.

If you have any questions, please contact your IDEXX representative or call Dr. Michelle Kahn at 1-207-556-8589.

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