Study uncovers FeLV test risks
Most accurate point-of-care test identified

More than 5 million cats across the U.S. are affected by feline
leukemia virus (FeLV) and feline immunodeficiency virus (FIV),
placing them at risk for disease and premature death.1 These arepreventable, contagious retroviruses. Identifying and segregating
infected cats is the key to controlling the spread of disease. As aWitness
Witness
result, positive cats may be euthanized based upon the resultsof a pet-side test.

In “high-stakes” testing, accuracy
could be life and death
Prevalence of FeLV is 3% in the population of tested cats.*Retroviral testing is “high stakes”
With retroviral testing, the stakes are high because the life of a pet
faces imminent risk. Accurate results are paramount.
•	A false-positive result means that a healthy, uninfected cat has
tested positive. A positive test result could lead to that cat being
euthanized unnecessarily.
•	A false-negative result means that an infected cat has been
missed and is considered free of the infection. If that cat isthen placed in a household with other cats, it could endanger
those cats.

Study

3 true positives + 4.5 false positives
The Witness test was only 95.5% specific in the Levy study1…thus a“positive” Witness test result was more likely wrong than right.
IDEXX showed 100% specificity.

New independent research conducted by Julie K. Levy, DVM, PhD,DACVIM, and her team at the Department of Small AnimalVetscan
Clinical
VetscanSciences at Maddie’s Shelter Medicine Program in Gainesville,
Florida, identified significant differences in sensitivity and specificity
provided by tests from leading manufacturers of in-clinic tests.
Dr. Levy’s study determined that the IDEXX SNAP® FIV/FeLVCombo Test demonstrated higher sensitivity and specificity for
FeLV than competing brands, including the Zoetis Witness® FeLVFIV Test and the Abaxis VetScan® FeLV/FIV Rapid Test, both ofwhich are lateral flow tests. This means the IDEXX SNAP test hadfewer false-positive and false-negative test results.1

FeLV test risks
The most significant findings of the Levy study pertained toFeLV. Both the Witness and VetScan Rapid lateral flow testsdemonstrated relatively poor specificity for FeLV, which means theygenerated false-positive results for healthy, uninfected cats. TheSNAP FIV/FeLV Combo Test generated zero false-positive results.
For instance, a test with 95% specificity would, on average, falselyidentify 5 out of 100 healthy cats as infected. This has increasing
importance when screening for a disease that has a low prevalencein the population. In a situation like FeLV, where the prevalencein the tested population is 3%,* a test with low specificity can
produce positive results that will more likely be wrong than right.

3 true positives + 14 false positives
The VetScan Rapid test was only 85.7% specific in the Levy study1…thus a“positive” VetScan Rapid test result was more likely wrong than right.
IDEXX showed 100% specificity.

Conclusion
Based on the data from this independent, head-to-head study
directly comparing in-clinic FeLV/FIV tests using the same sample
set, the IDEXX SNAP FIV/FeLV Combo Test demonstrated superior
performance in “high stakes” retroviral testing. And because inmany cases, the test result is the diagnosis, using an accurate
test where the result can be trusted is essential to providing quality
medical care.

*IDEXX results from 1.9 million tests in the U.S. from 2013 to July 2016. Data on file at IDEXX Laboratories, Inc. Westbrook, Maine USA.
Reference
1. Levy J. Performance of point-of-care assays for FeLV and FIV [ACVIM Abstract ID06]. J Vet Intern Med. 2016;30(4):1475.
© 2020 IDEXX Laboratories, Inc. All rights reserved. • 09-81968-02 • SNAP is a trademark or registered trademark of IDEXX Laboratories, Inc. or its
affiliates in the United States and/or other countries. All other product and company names and logos are trademarks or registered trademarks of theirrespective holders. The IDEXX Privacy Policy is available at idexx.com.