Concern level when pet has high liver enzymes?

Ask the Vet

Q: “Brewster” is my sweet little mutt that I adopted from the shelter a few years ago. We were just at the vet for his annual check-up, and my vet said his liver enzymes are high. Brewster is middle aged, but we don’t know his exact age. He is happy and active — how concerned should I be? P.R., Farragut

A: The primary liver enzyme in dogs is called ALT, and I assume that is what your veterinarian is referring to. There are also secondary liver enzymes, and there may be more cause for concern if those are also elevated.

Many things can cause ALT to be elevated. Primary liver disease is always a possibility. Additionally, certain medications can cause liver enzymes to be elevated, such as steroids or phenobarbital (a seizure medication). Some chemicals or toxins can also cause temporarily high levels; veterinarians see this often, as dogs get into the trash and lick/eat things outside they should not. Increased ALT can be secondary with certain medical conditions, such as diabetes or Cushing’s disease.

At Brewster’s annual visit, your vet likely performed a physical exam. An enlarged liver is generally palpable on exam, and a pet that is jaundiced will be noticed. It’s a good thing if your vet did not find this.

Depending on how high Brewster’s ALT is, your vet may discuss a few different scenarios. For slight elevations with no clinical signs, he/she might recommend liver antioxidants and a re-check blood test in a few weeks.

With higher enzyme levels, a liver ultrasound may be recommended — and even a liver biopsy. There is also a blood test that can tell us more regarding liver function. Your veterinarian, knowing Brewster and his medical history, will be able to guide you both through this.

If you have questions about your pet, please e-mail Dr. Myers at