Instructions
Observe your cat. Watch for any behavioral changes such as lethargy, anorexia and constipation. These are all signs of vitamin A toxicity.
Look for any physical problems developing in your cat. Cats with vitamin A toxicity usually lose weight, limp on the front legs, become sensitive in the neck and forelimb areas, and display stiffness.
Take your cat to its veterinarian for blood tests. The vet can run tests that will check the amounts of vitamin A in your cat's blood.
How to Tell If an Adult Cat Has a Vitamin A Toxicity
Typically, vitamin A toxicity in an adult cat occurs when the animal eats too much food that contains excessive amounts of liver. It also can occur if the cat has been given inappropriate amounts of supplements that contain vitamin A, such as fish liver oils, according to the veterinary website PetPlace.com. Cats that experience vitamin A toxicity usually display the same symptoms; however, the only way to know for sure is through a blood test.