Bloodwork

Many clients have heard from their veterinarian…”your pet need’s bloodwork”.  Bloodwork is fairly vague and can have many meanings from heartworm test to a full battery of tests sent to an outside laboratory.  This article aims to enlighten our readers about common types of ‘bloodwork’ that are performed both inside a veterinary hospital as well as sent to an outside reference laboratory.

Complete Blood Count (CBC) – measures blood cells and quantifies them.  Blood has several components but for simplicity, we will say it has 4.  Water, Red Blood Cells (RBC’s), White Blood Cells (WBC’s), and platelets make up the components.  A CBC can check for several things ranging from dehydration, infection, immune dysfunction, to blood clotting problems.

Water comprises anywhere from 40% to 75% of a normal dog’s blood.  Included in the ‘water’ component are electrolytes and blood proteins which do a myriad of things.  We can get this number by subtracting the RBC percentage (hematocrit) from 100.

Red Blood Cells (RBC’s) are the most numerous cells found in a CBC.  A hematocrit is the percentage of blood that is made up of red blood cells.  Other types of cells usually make up such a small fraction of the blood that a special bloodwork machine is required to accurately gauge them.

White Blood Cells (WBC’s) make up the portion of cells in blood that fight off infection.  A CBC machine or manual counter will differentiate the different types of white blood cells to better diagnose your pet’s illness.

Thrombocytes (platelets) are the cells that are responsible for clotting large defects of blood.  Platelets ‘stick’ together to make a seal to help stop bleeding from a wound.  If there aren’t enough platelets, animals can’t stop bleeding. Many CBC machines have difficulty reading platelets. For this reason, we perform blood smears and manually assess the platelet count on our CBC’s to verify their accuracy.

This is the CBC in a nutshell.

Blood Chemistry

Blood ‘Chemistry’ testing refers to testing for various chemical values in the blood.  While a complete discussion on each value would be beyond the scope of this article, we would like to familiarize you with things that are commonly included in a ‘blood chemistry profile’ so that you understand a veterinarian’s recommendations better.

Kidney Value – while it is impossible for most bloodwork to detect kidney function accurately, most chemistry profiles can detect significant malfunction of the kidney’s ability to get rid of waste products.   The kidneys have a large amount of reserve function, therefore MOST of the kidney must be damaged before routine chemistry profiles will begin to detect problems.  Unfortunately, there are few indicators of mild to moderate kidney damage in a routine profile.  Vets usually want to know if an animal’s kidneys are already in trouble before they perform certain procedures which can affect the ability of the kidneys to work.  One of the most common procedures that we would require kidney testing before performing is general anesthesia.  Another test, the urinalysis, is commonly performed along side a chemistry to better assess the kidneys.  There are many other tests that also test specific things about the kidneys but, again, are beyond the scope of this article.

Liver – There are several indicators of both liver damage and liver function in a routine chemistry panel.   Some tests, such as alanine transaminase (ALT) are a measure of liver damage.  Others, such as bilirubin and alkaline phosphatase, are general measures of biliary damage and/or function.  Test results for certain proteins and glucose can also show liver disease but usually only the most severe, end stage liver problems.

Diabetes – most blood chemistry profiles check blood sugar, the baseline test for diabetes.

Electrolytes – most general profiles also measure the primary electrolytes in the blood.  These are Sodium (Na), Potassium (K), Cloride (Cl), Calcium (Ca), and Phosphorous (PO4).   There are certainly other electrolytes but these five are the main, most significant ones.

Please stay tuned to this page as we will be filling in the blanks later!  As a typical article takes at least 2-3 hours to write and perfect, it will be many moons until our library is complete!  This particular article will likely take more time as it encompasses such a wide range of clinical syndromes.  Thanks for your patience. – Dr. Jay Taylor