The examining veterinarian will perform a blood test to determine the number of erythrocytes present in the animal's bloodstream. An in-hospital test called a "packed cell volume," or PCV, will approximate closely the percentage of red blood cells present. However, the veterinarian will typically opt to perform a complete blood count or CBC, which not only provides a more exact count of the red blood cells, but also measures the white blood cells and the platelets.
A CBC will tell the veterinarian whether the anemia is regenerative or nonregenerative. A regenerative anemia is one in which the bone marrow has released new red blood cells into the circulation in an attempt to replace the ones that were missing. If the initial CBC results suggest a nonregenerative anemia, it is possible either that the bone marrow has not had adequate time to react to the anemia or that the bone marrow is not able to produce the new red blood cells for some other reason. CBCs are usually run periodically until the patient's red blood count is stable and has returned to normal. If an animal has a true nonregenerative anemia, it will be necessary to determine the cause by means of further diagnostics. These may include fecal examination for blood parasites, urinalysis, serum chemistry, or bone marrow aspiration and evaluation.
