Heartworm Testing

Quick Reference

Heartworm Testing for Dogs
Heartworm Testing for Cats

How do you test for heartworm infection?

Heartworm testing requires a simple blood test and is necessary prior to starting a pet on heartworm prevention.

Why do pets need a heartworm test before starting preventions?

Heartworm testing is necessary as some of the heartworm preventions can cause a severe allergic reaction in your pet if they have heartworms. Testing is recommended twice a year but is usually required once a year for the purchase of heartworm prevention.

Why do I need a heartworm test when I know I have been giving the heartworm prevention?

Many clients ask why they still need a heartworm test even if they have given prevention. The FDA who licensed the heartworm prevention require the veterinarian to confirm that the pet is negative for heartworms before prescribing the drug. The only way a veterinarian can confirm that a pet is indeed heartworm negative is with a blood test. This is not saying that you the client did not give the prevention as directed. But, because the veterinarian did not give the prevention or wittiness the prevention being given, the veterinarian cannot certify that the pet is indeed negative for heartworms.

Is heartworm testing the same for cats and dogs?

Heartworm testing in cats only determines exposure to heartworms and only indicates that there may be a heartworm in the body of the cat. The heartworm test in dogs confirms that there are heartworms in the the major vessels feeding the lungs.
Heartworm positive dogs progress to heartworm treatment, while heartworm positive cats progress to more diagnostic tests. See the flow chart for diagnosis of feline heartworm disease.