Why Does My Cat Need Blood Work before Anesthesia?

Dr. Phil Zeltzman is a traveling, board-certified surgeon in Allentown, PA. His website is www.DrPhilZeltzman.com. He is the co-author of “Walk a Hound, Lose a Pound” (www.WalkaHound.com).

Zee Mahmood, a veterinary technician in Reading, PA, contributed to this article.

cat getting blood work done

Your veterinarian will likely require blood work before your cat has anesthesia for dental work or surgery. What is the point of running blood work? Is it a way to pad the bill? Is it a scam designed by veterinarians who want to retire on the beach?

Blood work is actually the easiest, fastest, cheapest and least invasive way to investigate, discover and monitor many health conditions. It is typically either sent to an outside lab or analyzed in-house, (i.e., at the clinic). Your cat's blood work is handled by well-trained technicians and performed on sophisticated, automated machines. The price of blood work is based on the cost of such advanced and accurate machines, sample preparation, sample handling by the nurses and the analysis by the veterinarian.

Why is blood work performed?
There are several reasons for this test, all with one goal in mind -- making sure that your cat is healthy enough for anesthesia and surgery. Since it is unlikely that your cat will tell the veterinarian what could be wrong inside, your veterinarian can use your cat's blood work to get a better understanding of what is going on beneath the surface.

What can be found from blood work?
There are two main parts in routine blood work: the chemistry and the Complete Blood Count (or CBC).

The chemistry consists of an analysis of various enzymes, proteins and other chemicals in the bloodstream. These levels can indicate healthy or unhealthy conditions of the organs. Liver function is analyzed to detect liver disease, Cushing's disease, trauma or the presence of a liver shunt, a rare condition that causes blood circulation to bypass the liver. Eliminating the possibility of a shunt is very important for any kitten undergoing anesthesia.

Kidney function is similarly analyzed to detect kidney disease. Ideally, kidney blood work goes along with a urinalysis to specify what type of kidney disease may or may not exist. Your cat's chemistry also investigates blood glucose or sugar. Electrolyte levels are measured to check for dehydration, metabolic disorders and kidney disease. The function of the pancreas and the thyroid function can also be tested. Older cats can have a hyperactive thyroid gland (hyperthyroidism), which is important to detect before anesthesia.

In addition to analyzing the chemistry of the blood, your veterinarian can run a Complete Blood Count. The CBC provides detailed information about the various blood cells and platelets. Low counts of certain blood cells can indicate hidden diseases such as anemia, bleeding or even bone marrow or immune system disorders. High counts of certain blood cells can indicate conditions such as dehydration, inflammation or infection.

Can blood work change a surgery date?
By performing these fast and minimally invasive tests, your veterinarian analyzes the inner workings of your cat -- especially important before anesthesia or surgery. If a problem exists in the blood work, it can determine whether surgery can be performed now, or if your cat's health should be managed with medications or IV fluids prior to, during or after surgery. Early detection of diseases is always of the utmost importance to keep your cat healthy. This is also the reason why we recommend blood work at every yearly physical exam, especially in older cats.

So the next time your veterinarian recommends pre-surgical blood work, you can rest easy knowing that there is much more than meets the eye when it comes to the findings your cat's blood will indicate. In the end, it’s all about making you happy and keeping your cat healthy.

Questions to ask your veterinarian

  • Why do you want to run blood work on my cat?
  • Will you call me with the results or should I call you?
  • How might blood work change what you do?

If you have any questions or concerns, you should always visit or call your veterinarian -- they are your best resource to ensure the health and well-being of your pets.


Reviewed on: 
Sunday, March 15, 2015