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

Blood Test For Cats

When your veterinarian recommends blood tests for your cat, you may be unsure of what they intend to find. Even the most seasoned pet owners can be terrified when they do not understand why their cat requires a medical procedure or what the outcome will be.

Below are some of the common blood tests done on cats and what they tell 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

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.

The correlation between creatinine levels and kidney function is stronger. High levels indicate that the cat's kidneys are having trouble eliminating creatinine from the body, and that kidney disease may be developing.

Alanine Aminotransferase (ALT) & Bilirubin

Blood panels frequently include blood chemistries such as ALT and bilirubin. They are generally indicative of liver health, and abnormally elevated levels typically indicate liver dysfunction.


If a cat has diabetes mellitus, the glucose level will be quite elevated. Low blood sugar levels can also provide vital information about a cat's overall health to a veterinarian.

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

    Kittens and adults are routinely tested for FeLV and FIV at regular intervals. It is essential to monitor your cat's status in relation to these viruses, as they are fatal and incurable once a cat has contracted them.

      Thyroxine (T4)

      T4 levels in cats are commonly monitored as they age. A high T4 concentration may indicate the onset of hyperthyroidism, a common condition in cats. A variety of symptoms, including increased appetite, weight loss, eating non-food items or wanting more human food, and increased vomiting, can be caused by elevated thyroid levels in cats.


      Electrolyte levels, which consist of potassium, sodium, and chloride, can tell a veterinarian a great deal about a cat's health, including hydration levels and organ function, particularly kidney function. Electrolyte imbalances in cats can result in a variety of symptoms, including arrhythmias of the heart and muscle weakness.

      Why Your Vet Might Suggest Blood Work

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

      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 - As part of routine wellness exams, blood tests are typically recommended for cats of all ages, from kittens to senior cats. When blood tests detect illness in its earliest stages, the health and happiness of our geriatric patients frequently return to normal. Bloodwork and other bodily fluids, such as urine, can help identify conditions that cannot be detected through a physical examination.

      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. Blood Work can also help determine the surgical risk level in all cats, especially elderly or injured patients.

      What Can Be Learned From Your Cats Blood Test

      The results of feline blood tests are essential to helping veterinarians diagnose and treat medical conditions both within the blood itself, as well as in organs such as the kidney and liver. During a blood test for cats, various chemicals in the bloodstream are analyzed. Some examples are:

      • 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 a connection has been established, we can order any additional feline bloodwork or procedures necessary to diagnose and treat the condition. In this way, feline blood tests are extremely valuable tools in a veterinarian's arsenal 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 Los Angeles vets to schedule an appointment today.