Canine Neutrophil Count for Chemotherapy

If your dog has been diagnosed with cancer and is about to undergo, or has undergone, chemotherapy treatments, your veterinarian may have informed you about the importance of checking the absolute neutrophil count. Neutrophils are a type of white blood cell that is used by your dog's body to fight infections. Monitoring their numbers during chemotherapy helps determine how the dog is responding to treatment and identify potential risks.

  1. Neuthophil Functions

    • Neutrophils play a key role in the dog's immune system. Their main function is to protect the dog's body by engulfing and killing disease-causing bacteria that invade the body and cause infection. Neutrophils are formed in the dog's bone marrow and present as mature or immature cells. Mature cells present a typical multi-lobed nucleus and are referred to as segmented cells, whereas, immature cells present a single-lobed nucleus and are commonly referred to as bands.

    Neutrophil Tests

    • Monitoring neutrophil counts is of primary importance to prevent neutropenia.

      Because chemotherapy drugs suppress the immune system by impairing the bone marrow's ability to produce cells, there are chances dogs may develop lower than normal neutrophil counts, a condition known as neutropenia. This generally occurs seven to 10 days after chemotherapy. Because of this, it is important for veterinarians to monitor neutrophils by performing a complete blood count. An absolute neutrophil count is obtained by calculating the number of neutrophils in a cubic millimeter of blood.

    Neutrophil Numbers

    • Neutrophil numbers are monitored carefully in chemotherapy patients.

      The unit used to calculate the number of neutrophils is per microliter of blood. Generally, the normal range for mature neutrophils is estimated to be between 3,000 to 12,000 per microliter, whereas the normal range for bands is considered to be approximately 100 to 300 per microliter, veterinarian Race Foster explains. Obviously, normal blood work values may vary slightly from laboratory to laboratory.

    Neutrophil Risks

    • Fever, weakness and lethargy are potential signs of severe neutropenia.

      The "nadir" is the lowest point of the neutrophil count following chemotherapy treatment. This is when your dog is most at risk for infection since the usual degree of protection from microbe invaders is lost. Symptoms such as fever, weakness, shivering, red mucus membranes, high heart rate, coughing, vomiting and diarrhea are warning signs that the dog is at risk for sepsis. This is most likely to occur with an absolute neutrophil count of less that 1,000 cells per microliter.

    Neutrophil Treatments

    • Carefully monitoring neutrophil counts during chemotherapy therefore helps in recognizing early signs of neutropenia. Should a low count be determined, chemotherapy medications can be adjusted accordingly and prophylactic antibiotic treatment may be initiated to protect the dog from infection. Subsequent periodic blood tests will also be performed to ensure the neutrophil count returns to normal levels.