URINE AND PARASITE TESTING
Heartworm Testing
Blood-based testing used to detect or assess heartworm infection, interpreted according to species, exposure history and preventive use.
THE SHORT VERSION
Testing helps answer a clinical question.
Heartworm testing commonly includes an antigen blood test in dogs; additional testing may look for circulating immature worms or use imaging when clinically indicated. Cats require a different, more cautious diagnostic approach.
What is this test?
Heartworm testing commonly includes an antigen blood test in dogs; additional testing may look for circulating immature worms or use imaging when clinically indicated. Cats require a different, more cautious diagnostic approach.
What information can it provide?
- Antigen testing commonly identifies proteins associated with mature female heartworms in dogs.
- Microfilaria testing looks for circulating immature stages and can add diagnostic information.
- Feline antigen and antibody testing have different strengths and limitations.
- Chest imaging or other studies may help when symptoms or test results suggest cardiopulmonary disease.
When might your veterinarian recommend it?
- Screen dogs according to veterinary and American Heartworm Society recommendations.
- Investigate missed preventive doses, uncertain history, cough, exercise intolerance or concerning exposure.
- Evaluate cats with respiratory signs, unexplained vomiting or other compatible concerns.
What can owners do before the visit?
- Provide the date of the last preventive dose and any missed or delayed doses.
- Tell the clinic about travel, previous heartworm infection and current symptoms.
- Do not restart, stop or double medication without veterinary guidance.
What can this test not tell you by itself?
- A recent infection may not be detectable immediately because worms require time to mature.
- A negative result does not always exclude disease, especially in cats.
- Heartworm testing does not replace consistent veterinary-recommended prevention.
Do not change medication, interpret an abnormal number as a diagnosis or delay urgent treatment without direction from your veterinary team.
Useful questions for your appointment
- Should antigen and microfilaria testing both be considered?
- How does a missed dose change testing or follow-up timing?
- Does my animal need species-specific prevention or additional imaging?