Many times, an abnormally high number of leukemic cells will be found in circulating blood on routine blood work, including a complete blood count and peripheral blood smears. The results of these tests can raise a high degree of suspicion that leukemia is responsible for the dog’s symptoms of unwellness. A serum biochemistry profile on a blood sample, and a urinalysis on a urine sample, can provide additional valuable information about the dog’s overall health.
The most definitive way to confirm a diagnosis of leukemia is by bone marrow aspiration and/or core biopsy. These procedures involve inserting a rigid, hollow needle into the marrow-containing center of long or flat bones and extracting a marrow sample into an attached syringe. In medium and large dogs, the preferred sample site is a specific area of one of the pelvic bones called the iliac crest; in smaller dogs, most veterinarians will take the sample from another area of the hip called the trochanteric fossa. These procedures require sedation or general anesthesia for immobilization and comfort of the dog, because they can be quite painful as skin, muscles, nerves and other tissues are penetrated by the biopsy instruments. The samples will be submitted to a diagnostic laboratory for microscopic assessment through a process called cytology.
Enlarged lymph nodes, liver and spleen can be sampled by taking fine needle aspirates and evaluating the samples microscopically, to determine whether the tissues are infiltrated with cancerous leukocytes. Thoracic (chest) and abdominal radiographs (X-rays), instead of or together with thoracic and abdominal ultrasound, may provide additional information to the attending veterinarian, such as revealing an enlarged liver, spleen, lymph nodes or other organs.
Dogs with leukemia have compromised immune systems. They should be isolated from other sick animals – especially those with infectious diseases - and probably should not be taken to dog shows, dog parks, boarding facilities or other areas that may have been frequented by dogs of unknown health status.