Heartworm testing in dogs is a simple process that involves only a few drops of blood. In many hospitals, it can be done extremely quickly, often in a matter of a few moments. Currently, available heartworm tests are accurate and reliable.

Contents at a Glance

What Dogs Should be Tested for Heartworms?

Any dog over the age of six months should be tested for heartworms. Dogs younger than six months of age do not generally need to be tested for heartworms but should be placed on heartworm preventive medication. The reason for the recommendation to test dogs six months of age and older for heartworms is due to the fact that it takes heartworms four to six months to mature and be detectable with heartworm testing. Prior to six months of age, it is nearly impossible for a dog to have a positive heartworm test.

Most dogs should be tested every 6-12 months for heartworms, even if receiving heartworm prevention medicine. There are many reasons for this:

  • dog owners may not be compliant with giving medication as directed, often without being aware of the fact
  • dogs may not be compliant about taking medications administered by dog owners, particularly if the medication is oral
  • heartworms are less likely to cause serious damage if heartworm disease is detected early
  • heartworm treatment is likely to be safer and more effective if heartworms disease is detected early

Annual Heartworm Testing is Necessary Because Sometimes Owners are Non-Compliant

All of us lead busy lives and it is not difficult to forget small things in our daily routines, particularly when the item is one that is done on a monthly basis. Sometimes, the time just gets away from us and we do not realize that it has been more than a month since we administered the heartworm preventive medicine to our dog. Other times, we may not have the heartworm medicine readily available and may need to postpone a dosage until we are able to get to the veterinary office to purchase the heartworm medicine or wait for it to come in the mail. Another scenario might involve two dog owners, each of which believes the other has administered the heartworm preventive medicine for the dog when the truth is that the dog has not yet received the heartworm preventive medicine. Whatever the reason, sometimes life takes over, other events occur and the heartworm preventive medicine does not get administered to the family dog, leaving the dog susceptible to heartworm infection and disease.

Prevent Heartworm With Dog Heartworm Medicine

Annual Heartworm Testing is Necessary Because Sometimes Dogs are Non-Compliant

We have all seen dogs that did not like to take medication. Dogs can be very clever, often appearing to have swallowed medicine which in fact has not been swallowed. Chewable flavored heartworm preventive medicines make this less likely, but still not impossible.

In addition, it is not impossible for a dog to vomit shortly after taking medicines of any type. Vomiting may the result of eating grass, chewing on plants, ingesting other foreign objects, viral infections, an “upset stomach”, and a host of other reasons. While occasional vomiting in itself may not be serious, if the dog vomits shortly after receiving the heartworm preventive medicine, he may also vomit the heartworm preventive medicine along with the rest of the stomach contents. Vomiting like this would be no different than if the dog never swallowed the heartworm preventive medicine and would result in the dog being susceptible to heartworm infection and disease.

Annual Heartworm Testing Provides Early Diagnosis of Heartworm Infection and Disease

Heartworm infection in dogs can lead to serious damage to the heart and can lead to heart failure and other symptoms. However, this damage does not take place overnight. When heartworm infection is detected soon after infection, the time the heartworms have to damage the heart is shortened.

Early diagnosis of heartworm infection is achieved by testing for heartworms annually. Annual heartworm testing can allow earlier treatment, reducing the chance of serious damage to the heart of the infected dog.

Annual Heartworm Testing Allows Early Treatment of Heartworm Infections

Treatment of heartworms in dogs is safer now than it was previously. However, heartworm treatment is still not without risk. Heartworm treatment which is performed early in the course of disease before the serious illness is observed is safer for the dog, with less risk of adverse side effects occurring. Treatment of heartworms is also more likely to be successful early in the course of the disease, again because of the lower risk of adverse side effects.

Annual heartworm testing allows earlier treatment of heartworm disease by allowing earlier detection of disease. For this reason, many veterinarians recommend yearly (or sometimes semi-yearly) heartworm testing for most dogs.

Precisely What Is Heartworm?