Enhanced WITNESS HW Heartworm Antigen Test Approved By USDA And Launches Today

Product Features Improved Sensitivity

MADISON, N.J., April 15, 2013 – Zoetis™, formerly the animal health business unit of Pfizer Inc., today announced the U.S. Department of Agriculture (USDA) has approved a newly-enhanced version of the WITNESS® HW Heartworm Antigen Test kit for dogs and cats. Launched today, the enhanced WITNESS HW test kit is now available to veterinarians nationwide.

Enhancements to the biologics, including test antibodies, improvements to the buffer and sample pad and improve the signal strength at the control line for better confidence in the results, translates to improved sensitivity in the convenient, affordable and versatile test.

“Veterinarians have depended on WITNESS HW since its introduction in 1997,” said J. Michael McFarland, DVM, DABVP and group director of Companion Animal Veterinary Operations for Zoetis. “The enhanced version of this trusted product provides veterinarians with accurate, easy to interpret results in approximately ten minutes so they can begin heartworm preventative treatment for their patients right away.”

In a recent study, WITNESS HW outperformed other Point of Care (PoC) tests on sensitivity1* by up to 13 percent. WITNESS HW has a twelve-month shelf-life and requires no refrigeration. Its unique immunochromatography RIM™ (Rapid Immuno Migration) technology is a streamlined process so no waiting to snap. Additionally, it is flexible because only one drop of sample, either anticoagulated whole blood, serum or plasma, is needed for testing.

“A reliable, affordable, fast-acting heartworm antigen test is an important tool for our clinic,” said Christopher Alvey, BS, DVM, of Bridge Mill Animal Hospital in Canton, Ga. “When clients can receive the results of their pets’ test while still in our clinic, it makes it easier for us to dispense a heartworm preventative or to begin treatment for affected animals. We have used WITNESS HW for many years and are pleased that the company has made it even more reliable.”

For more information on the enhanced WITNESS HW test, veterinarians may consult www.zoetisus.com/diagnostics or contact their Zoetis representative.

About Heartworm Disease

According to the American Heartworm Society (AHS), cases of heartworm have been diagnosed in all 50 states and changes to the environment and natural climate conditions, as well as animal movement, have increased the potential for heartworm infection in more areas around the country. Improved heartworm testing is considered one of the reasons why cases that may have gone undiagnosed in the past are now being found and treated.

The American Heartworm Society also recommends that, “Before starting a preventive program, all dogs should be tested for heartworms. Giving preventives to dogs that have adult heartworm infection can be harmful or even fatal to the pet.”2


WITNESS® HW detects the presence of adult Dirofilaria immitis antigens in dog or cat blood. The WITNESS®  format is referred to as Rapid Immuno Migration (RIM™). This technology is also sometimes referred to as lateral flow or rapid immunochromatography. WITNESS®  tests

1 Data on file, Study Report No. DH69W-US-12-001, Zoetis Inc.
* Sensitivity represents the ability to correctly identify positive samples.
2 2 Current Canine Guidelines for the Diagnosis, Prevention, and Management of Heartworm (Dirofilaria immitis) Infection in Dogs (revised January, 2012)

perform well without refrigeration using an antigen-specific antibody labeled with colloidal gold. After the sample and buffer are added to the sample well any antigens in the sample migrate across a nitrocellulose membrane along with the gold-labeled antibody (conjugate) and form an antigen/antibody gold complex. A second antibody specific to the antigen binds the antigen/antibody gold complex at the test line. In a positive sample, this generates a pink to purple colored reaction line in the result window. Excess colloidal gold-labeled antibody migrates across to the control line, where an antibody directed to the gold-labeled antibody binds to it. This causes formation of the colored control line. A test result should always be interpreted in the context of all available clinical information and history for the dog or cat. Cats testing negative for heartworm antigen may benefit from other diagnostic tests, including heartworm antibody assays.

About Zoetis

Zoetis (zō-EH-tis) is the leading animal health company, dedicated to supporting customers and businesses focused on raising and caring for livestock and companion animals. Building on a 60-year history as the animal health business of Pfizer, Zoetis discovers, develops, manufactures and markets veterinary vaccines and medicines, complemented by diagnostic products and genetic tests and supported by a range of services. The company generated annual revenues of $4.3 billion in 2012. It has more than 9,300 employees worldwide and a local presence in approximately 70 countries, including 29 manufacturing facilities in 11 countries. Its products serve veterinarians, livestock producers and people who raise and care for livestock and companion animals in 120 countries. For more information, visit www.zoetis.com.

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