National Heartworm Awareness Month: Why Does My Dog Need a Heartworm Test?

Why Does My Dog need a Heartworm Test?

April is National Heartworm Awareness Month! Our veterinarians at All Pets often get the question, “Why does my dog need a heartworm test?” The heartworm is a parasite that transmits through mosquitoes and get’s into your pet’s bloodstream. Once there, it can clog the arteries and damage the heart. These health threats can also harm your dog’s lungs. Therefore, the heartworm test is an essential part of any checkup to ensure your dog’s overall health.

Why Does My Dog Need a Heartworm Test?

Heartworm disease is a serious, progressive disease. There are few, if any, early signs of heartworm disease in dogs. Therefore, detecting their presence with a heartworm test is essential.

The heartworm test at All Pets requires just a small blood sample from your dog. It works by detecting the presence of heartworm proteins. If your pet tests, further tests may be necessary.

Risk for Heartworm Infection in Dogs

Many factors require consideration, even if heartworms do not seem to be a problem in your local area. Your community may have a greater incidence of heartworm disease than you realize—or you may unknowingly travel with your pet to an area where heartworms are more common. Heartworm disease is also spreading to new regions of the country each year. Therefore, the risk factors are impossible to predict.

For this reason, the American Heartworm Society recommends you get your dog testing every 12 months for heartworm and administer heartworm preventative 12 months a year.

Heartworm Medications and Heartworm Testing

While giving your dog heartworm medication is essential, heartworm testing is still necessary. Heartworm Preventative medication stops infection by killing the worms before they mature, reproduce and cause damage. However, there is no drug available that can stop the mosquito from carrying the larvae to your dog. Therefore, we have to stop them before they become damaging adults and make the infection worse with their offspring.

These drugs are effective by retroactive protection and work only against certain larval stages of the heartworm. For instance, if you give your dog a dose on November 1, the dose covers any susceptible larvae at that time (likely only ones he was exposed to in October). However, any larvae that are present, but too young to be susceptible will not be covered until the next dose (December in this example). Conversely, larvae that are too old and past the susceptible larval stages will be able to grow into adults and there is no medication to stop them here. Therefore, you can notice that any lapse could result in a larva slipping through and making it to adulthood where no preventative medication can kill it and you will not know that the adult worm is there at all without testing.

When Dogs Need Heartworm Testing

Why Does My Dog need a Heartworm Test?

It is necessary to test your dog annually for heartworm infection. Your vet at All Pets can perform this test during a routine visit for preventative care.

You can start heartworm prevention for puppies under 7 months of age without a heartworm test. It takes at least 6 months for a dog to test positive after it has been infected. However, it is essential to be tested 6 months after your initial visit, and again 6 months later and yearly after that to ensure your dog is heartworm-free.


We hope this answers the your questions on “Why does my dog need a heartworm test?” Annual heartworm testing is necessary, even when your dog is on heartworm prevention year-round, to ensure that the prevention program is working. Contact us here at All Pets with the link below for more information or to schedule your next appointment with us today!

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