Witness Heartworm (Canada)
This treatment applies to the following species:HEARTWORM ANTIGEN TEST KIT
(Dirofilaria)
I. General Information
WITNESS® Heartworm detects the soluble antigen D. immitis in dog or cat blood. The test is recommended for use when clinical history and/or signs suggest heartworm disease or where a rapid verification of heartworm infection is required.
Ii. Test Principles
WITNESS® Heartworm is a simple test based on Rapid Immuno Migration (RIM™) technology, which detects the presence of adult D. immitis antigens in dog or cat blood. Sensitized particles bound to heartworm antigens present in the sample (whole blood, serum or plasma) migrate along a membrane.
The complex is then captured on a sensitized reaction zone where its accumulation causes the formation of a clearly visible pink/red band.
A control band located at the end of the reading window (3) ensures that the test was performed correctly.
III. SAMPLE COLLECTION
● The test can be performed on unclotted whole blood anticoagulated with EDTA or heparin, serum, or plasma.
● Always collect samples with a sterile needle and syringe.
● Hemolysis does not significantly interfere with the test, but strongly hemolysed samples may partly obscure a weak positive band.
Iv. Sample Storage
Anticoagulated whole blood samples should preferably be tested immediately after collection but not longer than 4 hours after collection, if stored at room temperature.
If testing is further delayed, samples should be kept refrigerated (up to 7 days at 2 °C to 8 °C).
For long term storage, samples (serum and plasma only) should be kept frozen (-20°C; or colder).
V. KIT CONTENTS
● 10 or 25 Pouches, each containing 1 test device and desiccant.
● 10 or 25 Pipettes.
● 1 Saline Buffer dropper bottle (5.0 mL).
● Instructions for use.
VI. PRECAUTIONS
● Do not use this kit or any of its components after the expiration date.
● Kit should be stored at 2 °C to 25 °C. Kit should not be frozen.
● Use the test immediately after the pouch is first opened (within 10 minutes).
● Avoid touching or damaging the membrane in the sample well or the results windows.
● The WITNESS device should be placed on a flat, horizontal surface while performing the test.
● Use a separate pipette for each sample.
● Hold pipette and buffer bottle vertically when dispensing sample and buffer, respectively.
● Handle all samples as biohazardous material.
● Saline buffer is preserved with sodium azide.
● For animal use only.
● Dispose of contents/container in accordance with local/regional/national/international regulations.
Vii. Test Procedure
Important: Allow the sample and buffer drops to fall onto the membrane in the sample window. Do not touch pipette tip, buffer bottle tip, the sample or buffer drops directly to the membrane.
1. SAMPLE APPLICATION
● Tear open a pouch provided and place the test device on a flat horizontal surface.
● Holding the provided pipette vertically, add one drop of sample to the test well.

2. BUFFER DISPENSING
● Check that the sample has fully absorbed into the membrane.
● Remove the cap from the buffer bottle, hold it vertically and add two drops of buffer to the test well.
● Leave the test device flat during migration of sample/reagent complex through the reading windows.

3. READING TEST
● Wait 10 minutes, observe the presence or absence of pink/red bands in the reading windows (2) and (3).

Notes:
● It is possible to read the test before 10 minutes if two pink/red bands are clearly visible in the results windows (2) and (3).
● The presence of only one band in reading window (3), prior to the end of the development time (10 minutes), does not mean that the test is complete, as a test band may appear more slowly than the control band.
VIII. RESULTS
Valid Results
● Test is valid if a pink/red band is present in reading window (3).
Interpretation of Results
● Positive. One band in reading window (2), with one band in window (3): sample is positive for HW antigen.
● Negative. No band in reading window (2), with one band in window (3): sample is negative for HW antigen.
Invalid Test
● Invalid test: No band in window (3).

Note:
● A test result should always be interpreted in the context of all available clinical information and history for the dog or cat being tested. Cats testing negative for heartworm antigen may benefit from other diagnostic tests, including heartworm antibody assays.
SYMBOL DESCRIPTIONS

Zoetis Inc., 333 Portage St., Kalamazoo, MI 49007, USA
VLN/PCN 190/5018.08
US 1-888-963-8471
Canada 1-800-461-0917
www.zoetis.com
Imported by Zoetis Belgium S.A., Rue Laid Burniat 1, 1348 Louvain-la-Neuve, BELGIUM
40042059
CPN: 1198507.3
16,740 TRANS-CANADA HIGHWAY, KIRKLAND, QC, H9H 4M7
Order Desk: | 800-663-8888 | |
Technical Services Canada: | 800-461-0917 | |
Technical Services USA: | 800-366-5288 | |
Website: | www.zoetis.ca |
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Copyright © 2025 Animalytix LLC. Updated: 2025-05-29
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