Causes of Elevated and Low White Blood Counts in Dogs
A dog's white blood cells play a fundamental role in defending the dog's body against foreign intruders. Just as an army of soldiers, these white blood cells are ready to attack an defend the body from invading bacteria, viruses and fungi.
There are various types of white blood cells produced by the dog's body. These consist of the following:
A white blood cell count (WBC) blood test encompasses all these types of white blood cells. Normal WBC values are between 6,000 and 17,000 per microliter.
Neutrophils are created in the bone marrow and they work by engulfing foreign invaders such as bacteria. There mature neutrophils and immature neutrophils. Normal ranges of mature neutrophils are between 3,000 to 12,000/µ l normal ranges of immature neutrophils range between 100 to 300 per microliter.
When the numbers of neutrophils increase this often indicates bacterial infections or severe stress. When the numbers of immature neutrophils are high compared to the immature ones this often indicates some severe reaction. When the numbers of neutrophils decrease it can be indicative of a viral infection or sepsis (blood poisoning). When the latter happens, there are lower numbers of neutrophils in the blood because they are all concentrated at the location of infection.
Eosinophils are also produced in the bone marrow and the normal range is between 100 to 1200 per microliter. They work in the same matter as the neutrophils engulfing foreign particles. Their high numbers are often indicative of parasites or allergies. Low numbers instead suggest prolonged stress.
Produced in the bone marrow as well, their function is still unknown. Many times, they are not present in blood samples, however when they are high levels they may suggest parasitic infections such as heartworm.
Lymphocytes are produced by the lymph nodes and the spleen. Normal values are between 500-4,800 per microliter. When the lymphocytes increase this may be indicative of leukemia. When the lymphocyte numbers decrease this is indicative of initial stages of infections such as Parvo or a reaction to the use of steroids.
These are produced and stored by the spleen and bone marrow. Their normal values are between 100 to 1800 of these per microliter. Their numbers are not altered much unless there is leukemia.