What does it mean when a veterinarian
says she needs to run some blood work on your pet? Blood work - presurgical
or otherwise - is usually a combination of a complete blood count (CBC) and
a blood chemical analysis. Blood work is a basic evaluation tool. Pets, particularly
senior ones, should have a CBC at every annual examination. In addition, blood
work allows a veterinarian to monitor the progression of a pet's disease.
When the blood sample is drawn from your pet, both the cells and the fluid
they "travel" in are examined.
The cell part of the blood is examined in the CBC. The CBC determines the
number of erythrocytes (red blood cells), the number and type of leukocytes
(white blood cells), the number of platelets (thrombocytes), the hemoglobin
level, and the hematocrit (packed cell volume, PCV). Erythrocytes carry oxygen
throughout the body. Leukocytes fight infection and are part of the immune
system. There are five different types of white blood cells: neutrophils,
lymphocytes, basophils, eosinophils, and monocytes. Platelets are clotting
proteins and indicate how fast your pet's blood can clot; slow clotting can
be a serious problem. A CBC can tell your veterinarian if your pet has an
unusual number of erythrocytes (anemia, polycythemia), leukocytes (leukopenia,
leukocytosis), or platelets (thrombocytopenia).
A chemistry panel (blood chem, chemistry screen), tests kidney function,
liver function, electrolyte levels, etc. Blood chemistries are run on
the fluid in the blood sample. (The CBC is the examination of the cells in
the blood sample.)
The chemistry panel usually includes the following tests: alkaline phosphatase
(SAP, ALP), alanine transaminase (alanine aminotransferase, ALT), bilirubin
total (T Bili), blood urea nitrogen (BUN), creatinine, creatine kinase (CK,
CPK), sodium, potassium, glucose, total protein, albumin, etc. Alkaline phosphatase,
alanine transaminase, bilirubin, and albumin give your veterinarian information
about the pet's liver function. Blood urea nitrogen, creatinine, and creatine
kinase tell your veterinarian how well your pet's kidneys are functioning.
Alkaline phosphatase: Used extensively as a tumor marker, it is also
present in liver injury, bone injury, pregnancy, or skeletal growth (elevated
values). Growing animals have normally higher levels of this enzyme also.
Low levels are sometimes found in protein deficiency, malnutrition, and a
number of vitamin deficiencies.
Alanine transaminase: Decreased ALT in combination with increased
cholesterol levels is seen in cases of a congested liver. Increased levels
are also seen in liver damage, kidney infection, chemical pollutants, or myocardial
infarction.
Bilirubin (total): Elevated in liver disease, hemolytic anemia, low
levels of exposure to the sun, and toxic effects to some drugs. Decreased
levels are seen in people with an inefficient liver, excessive fat digestion,
and possibly a diet low in nitrogen bearing foods.
Blood urea nitrogen: Increases can be caused by excessive protein
intake, kidney damage, certain drugs, low fluid intake, intestinal bleeding,
exercise, or heart failure. Decreased levels may be due to a poor diet, malabsorption,
liver damage, or low nitrogen intake.
Creatinine: Low levels are sometimes seen in kidney damage, protein
starvation, liver disease, or pregnancy. Elevated levels are sometimes seen
in kidney disease due to the kidneys job of excreting creatinine, muscle degeneration,
and some drugs involved in impairment of kidney function.
Glucose: Elevated in diabetes, liver disease, obesity, and pancreatitis
due to steroid medications, or during stress. Low levels may be indicative
of liver disease, overproduction of insulin, or hypothyroidism.
Total protein: Decreased levels may be due to poor nutrition, liver
disease, malabsorption, diarrhea, or severe burns. Increased levels are seen
in lupus, liver disease, chronic infections, leukemia, etc.
Albumin: High levels are rarely seen and are primarily due to dehydration.
Low levels are seen in poor diets, diarrhea, fever, infection, liver disease,
inadequate iron intake, third-degree burns and edemas, and hypocalcemia.
Copyright 2004 - 2008 by the Veterinary Information
Network, Inc. All rights reserved.
This work was originally published by Veterinary Information
Network, Inc. (VIN) and is republished with VIN's permission.
The above information is simply informational. It's intent is not
to replace the advice of a veterinarian nor to assist you in making a diagnosis
of your pet. Please consult with your own veterinarian for confirmation of
any diagnosis. Your pets life may depend on it.
