The liver is one of the hardest working organs in your dog’s body, but many owners don’t think much about it until bloodwork shows a change or a dog starts showing signs of illness.

This month we are talking about what the liver does, what abnormal liver values can indicate, and what owners can watch for to help catch liver problems early.

The liver functions as a filter, storage facility and factory for the body.

As a filter, it takes a first pass at nutrients, bacteria, and other substances absorbed from the intestines. Blood from the intestines goes directly to the liver, where bacteria can be removed from the bloodstream, nutrients can be collected for other processes, and toxins can be filtered out.

Blood from the rest of the body also passes through the liver, allowing it time to remove medications and steroids the body produces, helping prevent buildup.

Once blood is filtered, useful building blocks are brought into liver cells for use or storage, while harmful substances are neutralized and excreted through bile. Bile drains into the intestines to eventually be expelled, while stored nutrients can be converted to support the body’s needs.

The liver can:

In addition, the liver processes a large portion of the body’s blood supply at any given time and can temporarily store blood when needed.

This is a remarkable workload for a single organ. Because the liver interacts with so many body systems, it’s easy to see how many illnesses, not just primary liver disease, can affect liver values. Fortunately, in many situations, the liver is able to heal once the damage or stress is removed.

Like many organs, the liver has reserve capacity, meaning bloodwork can remain normal even when the liver is under some stress.

Liver stress can happen from:  

Every category has many possible causes so when we find abnormal liver values, we usually consider:

How abnormal is the bloodwork? Mild changes may simply be monitored, while significant changes may require intervention.

Is there a known stressor? Sometimes another illness, such as heart disease or recent infection, may be contributing.

Does the liver need support or further evaluation? This depends on the individual dog, how stable they are, and available resources.

It is common in some situations to address other illnesses first and recheck the liver afterward to determine if the liver has an issue or was under stress that has resolved.

Additional testing may include:

Because there are so many possible causes a biopsy is sometimes needed for definitive diagnosis. There are situations where the exact cause may not be determined if risk and cost outweigh trial treatment.

Early detection can make a big difference. While the liver has an incredible ability to heal, it deals poorly with scarring, which is why recognizing concerns early matters so much.

The challenge is that early signs can overlap with many other illnesses, including illnesses that can themselves cause liver stress.

Early signs may include:

More liver-specific signs often appear only when disease is more advanced. These may include:

These signs suggest liver stress and should be evaluated by a veterinarian.

One of the best tools we have for early detection is routine screening bloodwork. When your dog comes in for a wellness visit, liver values are often included in screening panels.

In young dogs, mild elevations can be commonly seen (because the ranges are based on adults) and may reflect normal changes associated with growth.

Screening allows veterinary teams to identify concerns and provide support before pets show outward signs, which may reduce the risk of chronic changes resulting in scarring.

A common question after abnormal liver values are found is: What can we do?

That depends on why the liver is strained. Supplements such as SAM-e, milk thistle, and Denamarin are commonly used to support dogs with liver abnormalities, though which is most appropriate depends on severity and what other medications a dog is taking.

Always talk with your veterinarian before starting a supplement, especially in a sick dog. Supplements can interact with medications, and what is helpful for one dog may not be right for another.

Diet is another common question. In many cases, dietary adjustments are not needed. In severe cases, or in dogs with protein intolerance or specific hereditary conditions, specialized diets may be appropriate. But in many cases, a complete and balanced diet appropriate for life stage is sufficient.

If you are considering dietary changes, a veterinary nutritionist can be a valuable resource.