Laboratory Tests for Diagonosing Cat Liver Failure

Cat liver failure is one of the leading causes of death in cats, alongside heart disease. Because of the complex functions of the liver, a cat cannot survive without it. When the liver becomes diseased and fails to function properly, an array of medical conditions are presented. Determining whether or not a cat has liver failure can be done through a series of diagnostic laboratory tests.

An Overview of the Liver

In order to understand the effects of cat liver failure, a cat owner must first understand the functions of the liver. The liver is one of the largest organs in a cat's body. It has several life-sustaining functions, including:

• Releasing bile to aid in the digestion process
• Assisting kidney function by processing proteins that can be filtered through the kidneys
• Filtering blood by breaking down toxins
• Storing the major energy source glycogen
• Converting protein metabolism into urea

Because the liver supports and assists so many other functions of the body, life is not possible without this crucial organ.

Laboratory Tests

There are several laboratory tests that can be used to diagnose cat liver failure, some of them more sensitive to liver function than others. When liver dysfunction in a cat is suspected, the first test to be completed is known as a liver function panel. The panel includes the following elements:

• Albumin – Produced solely by the liver and released as a protein of plasma in the blood. Normal values for dogs: 2.6 to 4.0. Normal levels for cats: 2.6 to 4.3.
• Total bilirubin – Released by the spleen as a result of red blood cell destruction. Bilirubin is carried to the liver to be altered with glycuronic acid. Normal values for both cats and dogs are 0.2 to 0.8.
• ALT – Produced by liver cells in response to damaged liver cells. Levels for both dogs and cats should be between 4 and 90.
• AST – Found in liver cells but also other types of cells throughout the body. AST is not completely specific to liver function, but when combined with other lab values, it can help to assist with a more definitive diagnosis. Dog AST levels should be below 105, cats below 51.
• Alkaline phosphatase (ALP) – ALP can be found in other bodily cells, but it is predominantly produced by liver cells. This enzyme helps to regulate alkaline pH levels in the blood. Normal levels should be between 3 and 70 in dogs and cats.

Another laboratory test used to detect cat liver failure is a basic metabolic panel (BMP). It includes these elements:

• Blood urea nitrogen – Created by the liver through protein metabolism. Dogs: 7 to 24. Cats: 10 to 30.
• Creatinine – More specific to the kidneys, but because the kidneys and liver work together to filter toxins, it is considered an important piece of diagnosing cat liver failure. Dogs: 0.7 to 1.4. Cats: 0.8 to 2.0.