Instructions
Take your dog to the vet if it displays heartworm symptoms such as persistent coughing, exercise intolerance, loss of appetite or labored breathing. The vet will conduct a physical examination and heartworm tests to diagnose the infection. (See References 1 and 3)
Consult your doctor about performing a screening test such as a Knott's test. This test detects the presence of baby worms or microfilaria in your dog's bloodstream. The dog's blood sample is mixed with formalin, a chemical, and spun in a mechanical device called a centrifuge to concentrate any microfilaria present. The mixture is viewed under a microscope to detect microfilaria. The presence of microfilaria indicates that adult heartworms reside in the dog's pulmonary arteries. (See References 1, 2 and 3)
Conduct an antigen test, which is an extremely sensitive and accurate heartworm infection diagnosis test. Dogs that test negative for microfilaria in screening tests may test positive for adult heartworms in an antigen test. Antigen tests detect specific antigens or proteins produced by adult female heartworms. This test can be performed in-clinic or at veterinary reference laboratories. (See References 1, 2, 3 and 4)
The vet will obtain a blood sample of your dog to perform an antigen test. The blood is combined with a chemical and the fluid is placed on a heartworm test filter paper. The fluid spreads across the filter paper, which is impregnated with heartworm specific antibodies. A color change or a line developing at a set point on the paper indicates a heartworm infection. (See References 1)
Perform imaging tests such as heart and lung X-rays, ultrasound and angiography if your dog tests positive in antigen testing. Heart and lung abnormalities develop early in heartworm infected dogs. Imaging tests are a strong indication of heartworm infection and aid in the evaluation the severity of the infection and possible course of treatment. (See References 2 and 3)
How Is the Heartworm Test Performed for Dogs?
Heartworm is a potentially fatal canine infection and should be assiduously prevented. Performing an annual heartworm test on your dog is a key element in preventing and treating the infection. A heartworm test diagnoses the presence of the Dirofilaria immitis, a parasitic heartworm in your dog's bloodstream. There are several diagnostic procedures that can be used to detect the presence of heartworm in dogs. (See Resources 1, 2 and 3; References 1, 2, 3 and 4)