Blood Count and Urinalysis for Dogs
At some time in your dog’s life, it is highly likely
that laboratory tests will be performed. These can range from very simple
tests, such as fecal checks for parasites or heartworm tests looking for antigens, to sophisticated
bloodwork checking out various organs and their functioning. The most common
tests done to the blood and urine are discussed here. Blood samples are
normally taken from your dog’s vein-either a leg or the jugular vein in the
neck. Fasting is recommended before blood tests.
Complete Blood Count (CBC) or Hemogram
A CBC is done on blood taken
directly from your dog’s vein. The goal is to count the different types of
cells present in your dog’s blood. At the same time, an evaluation is made
about the types of cells and their health and life stages. Blood counts may be
lowered overall in dogs with bone marrow disorders and those undergoing certain
types of chemotherapy.
PCV or Hematocrit:
This test checks to see approximately how many red blood cells your dog has.
Blood in a tiny tube is spun in a centrifuge and the number of red blood cells
is given as a percent of the total blood volume. Normal dogs run about 35 to 50
percent. A low PCV indicates anemia, which could have a
number of causes from hemorrhage to liver or kidney disease. A high PCV is
often present in dogs who are dehydrated.
With the red blood cells (RBC), an actual count is made by estimating from
the number of cells spread on a slide and examined under a microscope. The
amount of hemoglobin present and the age and size of the red blood cells are
also measured. MCV is mean corpuscular volume, which is the average size of the
red blood cells. MCH is mean corpuscular hemoglobin (the substance in the red
blood cells that transports oxygen), which is the average amount of hemoglobin
inside a red blood cell. MCHC is the mean corpuscular hemoglobin concentration,
which is the average concentration of hemoglobin in the red blood cells,
expressed as a percentage. Your veterinarian or the laboratory technician will
also examine cells for maturity and for any blood-borne parasites.
An estimate will also be made of the total number of white blood cells (WBC)
in the sample. White blood cells include eosinophils (cells that fight parasite
infestations and are involved in allergies), and cells that fight infections or cellular
invaders, including neutrophils, lymphocytes, basophils, and monocytes. The
number of white blood cells such as lymphocytes may be increased in dogs with
certain cancers, as well. Normally, white blood cell counts rise with bacterial
infections, but if the infection is winning the battle, counts may be lower
than expected. Viruses may also lower the white blood cell count.