Biology Reference
In-Depth Information
BLOOD TESTS
The blood carries information about numerous body systems and organ
function.Values can change quickly, depending on what is being measured,
so a blood panel is a snapshot of what is going on inside a cat's body at
a particular time. Blood tests are not directly useful for evaluating the
central nervous system, intestinal function or bladder disease.
Many veterinary clinics have machines capable of doing some
blood tests, but all clinics send at least some samples out to a reference
lab.When results are conclusive, blood tests are wonderful for support-
ing a diagnosis. Unfortunately, cats don't always do what they are sup-
posed to, and results may not fit with the suspected disease.
Reference ranges are the values that have been established as normal
for a particular test on a particular machine. Often healthy cats have val-
ues outside of these ranges. The significance of a test result above or
below the reference range depends on the particular test. Minor eleva-
tions are significant in some situations, while in others a value might need
to be at least two times above normal to be important. Results always
need to be interpreted based on a cat's condition and clinical signs.
Blood samples are obtained from the blood vessels.The amount of
blood needed to perform tests depends on the number of tests run and
the equipment used. Many in-house blood chemistry tests can be per-
formed with a few drops of blood obtained through a leg vein. A full
panel sent to a lab requires several milliliters of blood, usually obtained
through the jugular vein.
CBC
CBC stands for complete blood count, and this includes white blood
cells, red blood cells and platelets. White blood cells respond to infec-
tion and inflammation. There are five types of white blood cells: neu-
trophils, monocytes, lymphocytes, eosinophils and basophils. Red blood
cells carry nutrients and oxygen to other cells in the body. Platelets are
important for blood clotting.
All of the blood cells are produced in the bone marrow and released
based on the body's need and normal aging of the cells. The different
blood cells respond to injury and other disease states within the body
in ways that are reflected in their counts.
Not every cat with an infection will have an elevated white blood
cell count. In fact, viral infections often cause low white blood cell
counts. Allergic reactions and parasites can cause elevations in feline
eosinophil (a specific type of white blood cell) levels. Cats with cancer
