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

Blood Test For Cats

When your vet suggests blood work for your cat, you may not be sure what they are looking for or even understand why. Even the most experienced cat owners can be terrified of not knowing why their cat needs a diagnostic test and what the results mean.

 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.

Creatinine levels are more related to kidney function. High levels of creatinine indicate that the cat's kidneys are having a hard time clearing the creatinine from the body. As such, kidney disease may be developing.

Alanine Aminotransferase (ALT) & Bilirubin

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


Glucose, or blood sugar, is usually tested to see if a cat has diabetes. If they do, the glucose level will be quite high. Low blood sugar levels can also give a vet important information about a cat's overall health.

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

    FeLV and FIV are routinely tested for in kittens and at regular times throughout adulthood. These viruses are life-threatening and cannot be cured, so it's critical to monitor your cat's status in relation to them.

      Thyroxine (T4)

      T4 levels in cats are typically monitored as they age. A high T4 level may be indicative of the onset of hyperthyroidism, a common condition in cats. High thyroid levels in cats can cause a variety of symptoms. These include increased appetite, weight loss, eating non-food items, wanting more human food, and increased vomiting.


      Electrolyte levels, which include potassium, sodium, and chloride, can inform a vet a lot about a cat's health. These include hydration levels and organ function, particularly the kidneys. Electrolyte imbalances in cats can cause a variety of symptoms, including heart arrhythmias 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 - Cat blood tests are usually recommended for all stages of life, from kittens to senior cats, as part of their routine wellness checkups. These are extremely beneficial for mature patients. 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 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 we've established a link, we can order any additional blood work or procedures needed to diagnose and treat the condition. In this way, cat blood tests are extremely valuable tools in a vet’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 Rock Hill vets to schedule an appointment today.