What Blood Tests Can Tell You about Your Pet’s Health

By December 1, 2022 No Comments

Although some pets let us know when they aren’t feeling well, many cats and dogs hide signs of disease and other health problems. Our advice? Regular screening tests can make all the difference when it comes to catching early signs of disease. And the sooner we know about a pet’s health issues, the sooner the veterinary team at Old Towne Animal Hospital can help.

When Should Testing Begin?

Routine screening generally starts with the pre-anesthetic screen before a pet is spayed or neutered.  This, and any pre-anesthetic screen, is performed so we can detect problems that could make it difficult or dangerous for your pet to undergo anesthesia.

Typical pre-anesthetic blood testing evaluates:

  • Red blood cells (RBC): Essential for oxygen supply throughout the body. Anemia (low RBC) increases the risk of anesthesia by limiting oxygen supply to vital tissues.
  • White blood cells (WBC): Can be low or high if the body is fighting infection or has an immunocompromising disease or cancer conditions.
  • Platelets: An important part of what helps our blood to clot and seal wounds. Having a low count before surgery warrants further workup to prevent excessive bleeding.
  • Glucose (blood sugar): Low values can indicate that your pet is prone to hypoglycemia (low blood sugar) and may require extra monitoring and glucose supplementation throughout the anesthetic and recovery period. Older pets may have low or high glucose values, raising concern for diabetes or cancers that cause poor glucose regulation.
  • Liver enzymes: Provides clues about the health of the liver. High values may indicate liver dysfunction. In puppies and kittens, elevations in specific enzymes can be due to a condition called a liver shunt, a condition where the liver doesn’t receive normal blood flow during development and therefore doesn’t develop properly. This can cause decreased liver function, meaning that the liver can’t process anesthetic medications normally, potentially leading to delayed anesthetic recovery or worse.
  • Kidney values: Can tell us how well your pet’s kidneys are functioning. This is important because the kidneys are responsible for removing anesthetic drugs from the body and promoting recovery. Also, certain medications can worsen already damaged or diseased kidneys. In puppies and kittens, this may be our first indication that they have congenital (since birth) kidney failure, and early intervention will improve their chance of a longer life.
  • Proteins like albumin and globulin: These are important indicators of pet health. Elevated globulin levels can be caused by infections, chronic inflammation, and some cancers. Normal albumin levels are vital for a safe anesthesia. This is because many anesthetic drugs attach themselves to albumin in the blood and then gradually let go of them, leading to a low level of drug in the bloodstream. If the albumin level is low, more medication will be free-flowing in the blood; this can cause more rapid and profound responses, potentially leading to depressed breathing or cardiac arrest.
  • Electrolytes [potassium (K), sodium (Na), chloride (Cl)]: Can be altered in many disease states and can affect surgical healing or suitability for anesthesia due to their effects on the heart rate and rhythm.


Testing for Adult Dogs and Cats (1 to 6 Years of Age)
We recommend running similar tests at least once during a pet’s adult years but ideally, pets are checked yearly during their annual health examination. We may also recommend additional tests based on your individual pet and our exam findings. Although we work hard to detect disease based on history and physical examination, screening lab work can provide more insight into your pet’s health. The results of these tests can also act as your pet’s normal baseline; if your pet becomes ill in the future, these baseline values are helpful comparisons for us to have to verify illness.

Testing for Senior Pets (7+ Years of Age)

Because pets age faster than people, their health conditions can change faster as well, which makes testing for early disease important as pets get older.

Senior pets often need additional tests, such as for thyroid hormone, since hypothyroidism in dogs and hyperthyroidism in cats is very common. Regular urine tests are also recommended to monitor for signs of early kidney disease or bladder infection.


Why Does Testing for Early Disease in Pets Matter?

Routine lab work, including blood and urine tests, can help us determine whether your pet has any diseases we need to treat. Detecting disease early allows for better and often less costly treatment.

Some diseases can cause similar changes in pets, so determining the cause of your pet’s illness is essential. Testing plays a big role in helping us figure out what’s wrong and how to properly treat your pet.


If a disease is detected early, your pet may have more options for care and maintain a higher quality of life. Your pet’s health, comfort and well-being matter to the team at Old Towne Animal Hospital.

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