What Is a 4DX Test and Why Is It So Important for Your Dog?
During your dog’s annual examination you are likely asked about heartworm prevention, as well as flea and tick prevention. If preventatives haven’t been given consistently, or if there has been a lapse in administration a 4DX test (or “Lyme test”, in our office we call it the “HWLET”) is often mentioned. This is a quick test that can be performed in the office with a small sample of your pet’s blood. It tests for four diseases; Heartworm, Lyme, Anaplasma, and Ehrlichia. The test detects antigen for Heartworm disease, meaning it finds the molecules that cause the body to produce an immune response. So a positive result for Heartworm disease indicates an active infection.
Unfortunately, the results for the tick-borne diseases (Lyme, Anaplasma, and Ehrlichia) are not as straight forward. The test can only detect antibodies for the tick-borne diseases; this means a positive result tells you there has been as exposure to the disease, but not whether or not an infection is actively present. Antibodies are the compounds a body produces when exposed to antigen.
What Symptoms Should You Watch For?
Heartworm Disease Symptoms:
Heartworms are transmitted by mosquitoes. Once infected, microscopic larvae travel through the bloodstream and settle in the heart and arteries. Early symptoms are often invisible, but as the disease progresses, your dog may develop:
Persistent coughing
Lethargy
Exercise intolerance
Weight loss
Decreased appetite
Tick-Borne Illness Symptoms:
Ticks transmit bacteria into the bloodstream, affecting red blood cells, platelets, and even the kidneys or nervous system. Watch for:
Limping or lameness
Lethargy
Bruising or bleeding
Loss of appetite
Seizures or neurological issues
Fever
What Happens If the 4DX Test Is Positive?
If Heartworm Disease Is Detected:
If the 4DX is positive for Heartworm disease the result is then verified with a second test. Another test to test for the microscopic larvae may be sent to the lab, or your pet’s blood may be examined under the microscope. Often, a combination of the aforementioned is performed. X-rays of your pet’s heart and lungs are often taken to evaluate for signs of heart enlargement or heart failure (often causing fluid to back up into the lungs). A complete blood count (CBC) and serum blood chemistry will be performed to look for signs the disease has impacted the organs, as well as red and white blood cells. After further testing has been performed, treatment is often initiated.
If Lyme Disease Is Detected:
There is a special antibody test, called the QC6, which can measure the amount of antibodies to Lyme disease present in your pet’s bloodstream when a 4DX is positive for Lyme that test is typically recommended. A low value is thought to indicate previous exposure, not active infection. If a QC6 comes back with a high value, treatment is typically initiated. Because more serious forms of Lyme disease can affect the kidneys when an animal tests positive the serum blood chemistry (part of this panel checks specific kidney enzymes), as well as the urine, are tested. If a positive pet has elevated kidney enzymes or protein present in its urine, it is likely the Lyme disease is affecting the kidneys and treatment should be started.
If Ehrlichia or Anaplasma Are Detected:
As with the other diseases a CBC and chemistry are performed to assess for organ damage, as well as signs the red and white blood cells, and platelets are affected. If Ehrlichia is present the urine will typically be checked for protein as well. If the tests show signs of infection then treatment will be started.
Treatment for Heartworm disease is usually a series of injections of high doses of a chemical dewormer, as well as oral antibiotics and heartworm preventative. The tick-borne diseases are treated with an oral antibiotic, usually over the course of one month.
How can I prevent my pet from being exposed to these diseases?
The very best prevention is monthly heartworm prevention and monthly flea and tick prevention. The preventatives are available in many different forms; from topical liquid to oral chews, to collars. In our area, yearly administration of preventatives is recommended, as our weather is no longer consistently cold enough to eliminate ticks. Yearly administration also helps to develop a pattern of administration, making missed doses less likely.
During your pet’s next wellness visit you may hear the recommendation for annual 4DX testing. It could diagnose a disease early, allow for early treatment, and even a negative test can give you information about the effectiveness of your monthly preventatives. Our clinic has recently implemented a Wellness Profile that includes a 4DX. The profile also includes all of the follow-up tests that are typically performed for the tick-borne diseases, a urine protein quantification test and QC6 (for Lyme antibody) are usually add on tests that require an extra charge, they are now included for no extra charge. Consider testing your pet yearly to increase their longevity and your peace of mind!
Early Detection = Peace of Mind
Whether your dog is overdue on prevention or up-to-date, the 4DX test offers a powerful glimpse into their overall health. Even a negative result provides reassurance and helps us guide your preventive care plan.
