In a study of liver function tests, including alanine aminotransferase, alkaline phosphatase, and bile acid concentration, researchers found that more than half of a group of Labrador retrievers had values within the normal reference range while displaying signs of liver inflammation on biopsy. These tests may not be sensitive enough to identify dogs with acute or chronic hepatitis before clinical signs develop.
Read more about the study of liver function tests in Labradors in American Veterinarian. The original research can be viewed in the Journal of Veterinary Internal Medicine.
More about hepatic disease in dogs and cats can be found in the Merck Veterinary Manual.