This week one of our readers asked me what the normal blood glucose range is for dogs and cats. One of her vets told her it was up to 170 mg/dl for cats. I agree! It can be that high if taken in a clinic environment where a cat may feels stress. Evaluations in a pet’s blood glucose do reflect the environment and stress level of the pet.

Imagine that you were a cat. You were purr-fectly happy sunning yourself on the back of the couch in the family room by the big window. Ah, that’s the life. Suddenly, and without warning, your human nabs you and shoves you (despite your best Houdini-like efforts) into a box and puts you in the car. Oh how you hate going in cars! The car ride ends and you pray your human has come to her senses but no… You have arrived at the vet clinic and there are yapping dogs in the lobby. Even a non-diabetic cat could have a blood glucose level of 170 or more after such a harrowing experience. I’m not kidding. I live one mile from my own veterinary hospital and when I take my cats to work for a dental check or something else that I can’t do at home they scream in their carriers as if someone was beating them with a stick.

This phenomenon is called “stress hyperglycemia”. It’s not unique to cats. I once saw a Chihuahua present to the ER with a blood glucose level in the 300s from stress hyperglycemia. This is all part of the fight or flight response.

How does stress hyperglycemia occur? Remember learning about the fight or flight response back in high school? It’s that same thing. In a stressful situation you release adrenaline (a.k.a. epinephrine), which can cause the liver to produce more glucose to help you get away from the adversity. Cats are specialists in stress hyperglycemia.

In my hospital I use in house blood machines and also send blood to an outside reference laboratory when I need a blood profile. The “normal range” for the parameters we measure (such as kidney values, liver values, electrolytes and such) are different for each type of machine. I typically place more confidence in outside reference labs over in house machines, because their “quality control” is very tight. I run in-house labs when I need answers ASAP when a pet is ill or if I’m suddenly needing to anesthetize a pet that we hadn’t planned for ahead of time. For my outside reference lab (a big national lab), the blood glucose range for cats is 64 to 170. And for dogs it is 70 to 138. My in house chemistry analyzer lists a normal range of 70 to 150 for cats and 60 to 110 for dogs. It’s all statistics. They test a bunch of “normal” pets to determine a normal range with that chemistry analyzer. Ranges for various machines are in the same ballpark – but not exactly the same exact numbers.

Now, if we are trying to fine tune a pet’s insulin dose to get the best glucose regulation, and therefore the best quality of life for your sweetie, doesn’t it make sense to avoid factors that can cause stress hyperglycemia? You bet! This is why I’m such a huge proponent of home glucose testing. Additionally, it saves families lots of money compared to having glucose tests run at the clinic, where stress hyperglycemia can affect accuracy.

As always, I enjoy hearing from our readers and clients. You can email me at I get a lot of our article topics from questions by readers.

NOTE: Consult your veterinarian to confirm that my recommendations are applicable for the health needs of your pet.