We Decode Your Cat’s Blood Test Results

Blood tests are crucial for monitoring your cat’s health. Whether it’s a pre-anesthetic blood workup that monitors the function of certain organs necessary for processing anesthesia or a more comprehensive senior panel that measures a couple dozen different attributes, this information can help your vet keep your furry friend healthy for many years to come.

Your vet understands what all these different tests measure, and today I’m going to take the mystery out of feline blood test results for you.

The first part of the test is the complete blood count, or CBC. This measures the numbers of various types of cells present in your cat’s blood.

1. RBC and HCT (or PCV)

The RBC, or red blood cell count, measures the number of circulating red blood cells. Red blood cells carry oxygenated blood from the lungs to the rest of the body, which is crucial to sustain life. The hematocrit (HCT), sometimes known as the packed cell volume (PCV), measures the percentage of blood comprised of red blood cells. A low HCT indicates anemia or dehydration.

2. WBC, Lymph, Mono, Eos, Baso

The WBC, or white blood cell count, measures the number of immune cells circulating in your cat’s blood. A high WBC can indicate infection, while a low WBC is often seen with diseases such as FIV or feline leukemia. Lymphocytes (Lymph) are directly related to the immune system, while monocytes (Mono) are cells that engulf foreign bodies like bacteria or viruses. A high eosinophil (Eos) count can indicate allergies or parasitic infections, and basophils (Baso) can be associated with heartworm disease and allergies.

3. PLT

Platelets (PLT) are cells that form blood clots. A low platelet count indicates a cat may not be able to stop bleeding as easily as a cat with a normal platelet count.

The next set of values refers to "blood chemistry," the amount of certain enzymes, hormones and chemicals in the blood. Abnormalities in these values can point to various illnesses and organ dysfunctions.

1. GLU

The blood glucose (GLU) level is an indicator of how well the pancreas is working. If a cat’s glucose is too high, the cat is likely to be diabetic. However, because stress also can cause dramatic increases in the blood glucose level — and vet visits are really stressful — a cat’s glucose level can test artificially high during a clinic visit.

2. BUN and CRE

Blood urea nitrogen (BUN) and creatinine (CRE) are indicators of kidney function. Urea and creatinine are waste products of your cat’s metabolism, which are filtered out through the kidneys. In cats with chronic kidney disease, the BUN and creatinine values become elevated.

3. Sodium, potassium and chloride

These chemicals, known as electrolytes, play a critical role in proper nerve function. Nerves regulate everything from movement to vision all the way down to functions like breathing, heartbeat, and digestion. The kidneys play a crucial role in the balance of electrolytes, particularly sodium and potassium. Cats lose potassium and chloride very quickly if they’re vomiting or not eating.

4. ALP (or ALKP), ALT, and AST

These tests help to evaluate liver function. Elevated levels of alkaline phosphatase (ALP or ALKP) can be found in cats with liver damage due to toxin ingestion or certain medications. Infections, toxins, cancer, and metabolic diseases can cause elevated levels of aspartate transaminase (AST). If the alanine aminotransferase (ALT) reading is too high, it is almost always because of liver disease.

5. T4

Your cat’s total thyroxine (T4) level shows how well her thyroid gland is working. If the T4 level is too high, that means the cat is suffering from hyperthyroidism. If your cat’s T4 level is too low, that means they’re either getting too much medication to treat hyperthyroidism or it could be a complication of other chronic diseases.

Most comprehensive blood panels measure about 40 values, but the ones I’ve mentioned here are associated with the most common health issues in cats.

Do you want more medical jargon decoded? Want to know more about a feline health issue? Let me know in the comments, and I’ll gladly be your Rosetta Stone!

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• Weird Cat Facts: 8 Reasons Your Cat Likes to Lick You
• Our Best Tips for Getting Your Cat to Let You Sleep

About JaneA Kelley: Punk-rock cat mom, science nerd, animal shelter volunteer and all-around geek with a passion for bad puns, intelligent conversation, and role-play adventure games. She gratefully and gracefully accepts her status as chief cat slave for her family of feline bloggers, who have been writing their award-winning cat advice blog, Paws and Effect, since 2003.