How Do You Test for Heartworm Disease?

Heartworm disease is a serious infectious disease caused by a blood borne worm that lives in the heart and lungs of infected pets.

Heartworm is transmitted by mosquitos and infects both cats and dogs, maturing in the pet’s tissues and vascular system Once mature, the worms live in the pulmonary arteries entering the heart from the lungs, obstructing blood flow and causing inflammation and damage to the surrounding tissue.

Symptoms of heartworm disease may include persistent coughing, fatigue with exercise, reluctance to exercise, shortness of breath or laboured breathing, reduced appetite, weight loss or a swollen abdomen. In many dogs there will be almost no signs of heartworm disease until the late stages when the pet is already going iinto heart failure. Not only is this condition highly fatal, but treatment for cats and dogs can be complex – so prevention is key. Dogs tend to be more severely affected than cats.

Testing for heartworm is an essential step in keeping your pet safe and healthy. Here is everything you need to know about how heartworm testing works and why it’s so important.

How Do Vets Test for Heartworm in Dogs?

The most common way vets test for heartworm disease in dogs is through a blood test. This test is quick and relatively simple, offering fast and accurate results. A small blood sample is taken from your dog and tested for the presence of heartworm proteins, known as antigens, which are released by adult female heartworms.

What Does a Heartworm Test Consist Of?

Initial Antigen Test: This test detects heartworm antigens in the blood. It’s effective in diagnosing adult heartworm infections but may not detect immature worms or very early infections. In rare cases it can also miss infections where only adult male heartworms are present.
Microfilariae Test: If the antigen test is positive, your vet may recommend an additional test to check for microfilariae (baby heartworms) in the bloodstream. This confirms an active infection and helps assess the severity of the disease.

When to Test for Heartworm

Adult Dogs: Testing is typically recommended once a year as part of your dog’s routine health check.
Newly Adopted or Unprotected Dogs: If your dog has not been on a consistent prevention program testing is recommended before starting preventative medication.
After a Missed Dose of Prevention: If you’ve missed a dose of your dog’s heartworm preventative, a test may be necessary to ensure they remain heartworm-free.

Can You Perform an At-Home Heartworm Test for Dogs?

While at-home heartworm test kits are available they are not as reliable as those conducted by a veterinarian. These tests may fail to detect early-stage infections and can provide inaccurate results. Regular vet-administered blood tests are the gold standard for accurate and timely detection.

What is the Cost for a Heartworm Test?

The cost of a heartworm test varies depending on the specific test required. On average, a standard antigen test ranges from $50 to $100 in Australia [1] [NC2] . If further testing or additional diagnostic work is needed, such as X-rays or ultrasounds to assess organ damage, the cost may increase.

Why Testing Is Critical

Heartworm disease progresses silently, often showing no symptoms until severe damage has occurred. Untreated, it can lead to heart failure, lung disease, and ultimately death. Testing your pets is especially crucial because prevention medications cannot kill adult worms and administering preventatives to an infected dog can lead to severe reactions. Early detection allows for more effective treatment and a better prognosis.

Testing and Prevention

Testing for heartworm is an essential part of a comprehensive prevention plan. Even if your pet is on year-round prevention, annual testing ensures the medication is working effectively. For more information on preventing heartworm disease and treatment options, check out our detailed guide on Heartworm Disease and Treatment.

Book a Heartworm Test Today

Regular heartworm testing can save your pet’s life. Contact your local Greencross Vets to book a test and keep your furry friend heartworm free.