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Understanding Blood Tests for Cats

Blood tests play a crucial role in most veterinary clinics as a valuable tool for assessing the health of cats. In today's blog, our vets in Apple Valley emphasize the significance of blood tests for cats and highlight the valuable information they can provide to your vet.

Blood Testing for Your Cat

When your veterinarian suggests blood work for your cat, you might not precisely understand their objectives. The lack of knowledge about the purpose behind your cat undergoing a medical procedure and the significance of the results can be unsettling, even for the most seasoned pet owners.

Here, we outline some common blood tests performed on cats and elucidate the information they provide to the veterinarian.

Complete Blood Count (CBC)

A CBC measures and examines a cat's blood cells. It gives the veterinarian a wealth of information. Some of these include:

  • Red blood cell (RBC) counts, proportions, and health - RBCs carry oxygen, iron, and other nutrients around the body.
  • White blood cell (WBC) counts, proportions, and health - WBCs help fight inflammation, infection, cancer cells, and parasitic intruders.
  • Platelet counts and health - Platelets control blood clotting.

A CBC can tell a veterinarian if a cat is anemic, dehydrated, fighting off inflammation or an infection, and whether your cat has internal bleeding.

BUN & Creatinine

Blood chemists routinely measure blood urea nitrogen (BUN) and creatinine as part of comprehensive blood panels. A high BUN level can indicate dehydration, kidney dysfunction, or a liver problem.

Creatinine levels strictly reflect kidney function. Elevated levels suggest the cat's kidneys are struggling to clear creatinine from the body, potentially signaling the development of kidney disease.

Alanine Aminotransferase (ALT) & Bilirubin

ALT and bilirubin often appear in routine blood panels as blood chemistries. They primarily indicate liver health, and elevated levels usually suggest a liver malfunction.


Testing for cat diabetes mellitus primarily involves checking glucose or blood sugar levels. A veterinarian assesses whether a cat has diabetes by examining elevated glucose results. Low blood sugar levels also provide valuable insights into the cat's overall health.

    Feline Leukemia Virus (FELV) & Feline Immunodeficiency Virus (FIV)

    Kittens undergo routine testing for FELV and FIV, with periodic examinations continuing into adulthood. Since these viruses are life-threatening and incurable once a cat becomes infected, monitoring the cat's status is crucial.

      Thyroxine (T4)

      As cats age, veterinarians typically monitor T4 levels. Elevated T4 levels may suggest the onset of hyperthyroidism, a frequently diagnosed condition in cats. Increased thyroid levels can manifest in various signs in cats, such as heightened appetite, weight loss, consumption of non-food items or a desire for more human food, and increased frequency of vomiting.


      A veterinarian can glean valuable insights about a cat's health status, such as hydration levels and organ function, particularly the kidneys, by assessing electrolyte levels like potassium, sodium, and chloride. Electrolyte imbalances may manifest in various signs of illness in cats, such as heart arrhythmias and muscle weakness.

      Why Your Vet Might Suggest Blood Work

      Your vet might recommend bloodwork for your cat for various reasons. Here are the most common ones:

      It's your cat's first exam - We recommend blood work at the time of your cat's first exam because it helps us establish baseline health, check for any congenital abnormalities or potential concerns, and help us form an individual wellness plan for your cat.

      During semi-annual and annual wellness exams - Cat blood tests are usually recommended for all life stages, from kittens to geriatric cats, as part of their routine wellness checkups. These are extremely beneficial in our mature patients, as we often see cats' health and happiness return to normal when blood tests catch illness early. Cat bloodwork and other bodily fluids like urine can help identify conditions the examination portion of a physical cannot.

      If a cat seems sick - Cat blood tests are suitable for cats that are not displaying any overt signs of illness, disease, or injury but are acting abnormally.

      Before surgery - Cat blood work is used to determine the general health of the liver, kidneys, and other organs, which helps a veterinarian select the safest form of anesthesia. Bloodwork can also help determine the surgical risk level in all cats, especially elderly or injured patients.

      Cat Blood Test Results Explained 

      Feline blood tests play a crucial role in aiding veterinarians in diagnosing and treating medical conditions affecting both the blood and organs like the kidneys and liver. These tests involve analyzing various chemicals in the bloodstream. Here are some examples:

      • Cat blood tests can indicate a deficiency in albumin levels, which indicates a possible liver issue because albumin is produced in the liver or intestinal or kidney issues, as albumin can be lost if these are diseased.
      • Blood tests for cats can detect abnormal hormonal-chemical responses to environmental and internal stimuli, which indicates a potential issue with the patient's endocrine system.

      Once we establish a correlation, we can order any subsequent feline bloodwork or procedures necessary in diagnosing and treating the condition. In this way, feline blood tests serve as very valuable tools in a veterinarian's toolkit for helping to detect, identify, diagnose, treat, and ultimately prevent illness or disease.

      Note: The advice provided in this post is intended for informational purposes and does not constitute medical advice regarding pets. For an accurate diagnosis of your pet's condition, please make an appointment with your vet.

      Is your cat showing signs of a veterinary emergency? Contact our Apple Valley vets right away.

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