Description:
Blood is collected from an animal and placed into a tube which contains material that stops clots from forming. The blood cells themselves are then analyzed according to their shape, size, color, and relative numbers present in the bloodstream (hence the term "count").Diagnostic Value: High. Certain diseases can be detected and even initially diagnosed with a simple CBC. Problems such as anemia, severe infections, and some types of cancers can be detected.
Risks to Patient: Virtually none, provided that the blood is collected under sterile conditions by a trained professional.
Relative Cost: Low.
Normal Ranges: The following chart lists the normal ranges for many of the common items found on a CBC:
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PCV |
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RBC |
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Reticulocytes |
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Platelets |
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Segmented Neutrophils |
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Band Cells |
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Lymphocytes |
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Eosinophils |
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Interpretation of Results:
- A high PCV occurs most commonly with dehydration and certain heart defects.
- A low PCV can be the result of not enough red blood cells (anemia) or the occasional state of over-hydration.
- Low numbers of RBCs (anemia) can be the result of blood loss, inadequate RBC production in the bone marrow, or actual destruction of the RBCs within the body.
- High numbers of reticulocytes indicate a regenerative response (i.e. the bone marrow is producing more red blood cells).
- When low numbers of reticulocytes occur and anemia is present, there is usually a bone marrow malfunction.
- If low platelet numbers occur, the animal may be prone to bleeding disorders.
- High numbers of neutrophils (neutrophilia) occur when there is an infection, the animal is stressed (coming to the clinic), or when steroids have been administered.
- Low neutrophil numbers (neutropenia) can occur with very severe infections, some viral infections, and when there has been long term bone marrow damage.
- The presence of band cells usually indicates that an infection is occur- ring in the body. When high numbers of band cells are observed, it is called a "left shift."
- High levels of lymphocytes (lymphocytosis) can occur when the animal is excited or if there is a cancer of the bone marrow, such as leukemia.
- Low lymphocyte numbers (lymphopenia) indicate administration or release of steroids, viral infections, or stress.
- High numbers of eosinophils indicate a possible parasite problem, allergic reaction, or certain cancers.
This section lists only a few of the most common possibilities for cell changes in a CBC. A physical examination, additional history, and other tests may be required before a specific diagnosis can be determined.