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Cat Blood Test Results, Explained

Blood tests for cats are a valuable tool in most veterinary clinics. Our Stuart vets explain why blood tests for cats are important and what each test result might mean.

Blood Test For Cats

When your veterinarian suggests blood work for your cat, you may not understand what they are looking for. Even the most experienced pet owners can be terrified of not knowing why their cat needs a medical procedure and what the results mean.

Below are some of the common blood tests done on cats, what they tell the veterinarian, and why they are important.

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

BUN and creatinine are two blood chemistries that are routinely measured as part of larger blood panels. A high BUN level may indicate dehydration, kidney dysfunction, or a liver problem.

Creatinine levels are more strictly related to kidney function. High levels indicate that the cat's kidneys are having difficulty clearing the creatinine from the body and that kidney disease may be developing.

Alanine Aminotransferase (ALT) & Bilirubin

Blood chemistries such as ALT and bilirubin are frequently found in routine blood panels. They are mostly indicative of liver health, and if they are abnormally high, it usually indicates liver dysfunction.


Glucose, or blood sugar, is typically tested to determine whether a cat has diabetes mellitus. If they do, the glucose level will be very high.

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

    FeLV and FIV tests are performed routinely in kittens and at regular intervals throughout adulthood. These viruses are life-threatening and cannot be treated once your cat has been infected, so it is critical to monitor your cat's status in relation to them.

      Thyroxine (T4)

      T4 levels in cats are usually monitored as they age. A high T4 level could signal the onset of hyperthyroidism, a common condition in cats. Cats with high thyroid levels may exhibit a variety of symptoms, including increased appetite, weight loss, eating non-food items or craving more human food, and increased vomiting.


      Electrolyte levels can provide a veterinarian with valuable information about a cat's health, including hydration and organ function, particularly of the kidneys. Electrolyte imbalances in cats can result in a variety of symptoms, including heart arrhythmias and muscular weakness.

      Why Your Vet Might Suggest Blood Work

      There a many reasons your vet might suggest bloodwork for your cat. Here are the most common:

      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 tailored wellness plan for your cat.

      During semi-annual and annual wellness exams - Cat blood tests are usually recommended for all life stages 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, along with 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 a good idea for cats that are not displaying any overt signs of illness, disease, or injury, but are acting abnormally.

      Before surgery - Cat bloodwork 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 cats, especially elderly or injured ones.

      What Can Be Learned From Your Cat's Blood Test

      The results of feline blood tests are critical in assisting veterinarians in diagnosing and treating medical conditions both in the blood itself and in organs such as the kidney and liver. Cat blood tests analyze 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've established a link, we can order any additional feline bloodwork or procedures needed to diagnose and treat the condition. In this way, feline blood tests are extremely valuable tools in a veterinarian's toolbox for detecting, identifying, diagnosing, treating, and ultimately preventing 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.

      If your cat is displaying abnormal behavior, a blood test may be in order. Don't hesitate to contact our Stuart vets to schedule an appointment today.

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      Our Stuart vets can't wait to meet you! Our welcoming and accommodating team is passionate about the needs of your pets. Reach out to us today to book your pet's first appointment.

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