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Will a Blood Test Show Cancer in Cats? What Will It Show?

Chris Dinesen Rogers

By Chris Dinesen Rogers

Cat getting blood sample

There’s no denying the value of blood tests. They can diagnose lots of things, from infections to anemia. They provide veterinarians with information about your pet’s health that may not be evident. Lest we forget, cats will hide when they feel sick. It’s their way of not showing their vulnerability cards. These tests may also play a role in detecting the disease and directing a course of treatment. The short answer is that blood tests can sometimes show cancer in cats. Keep reading to see why it’s complicated:

Defining Cancer

It’s helpful to begin by defining cancer to understand how blood tests may work for treating this condition. Cancer isn’t a single disease but over 100 different ones. Each has its risk factors and chemical pathways that determine its course. As a catch-all term, it describes a situation where cells grow abnormally, whether their structure or numbers.

This out-of-control growth can cause tumors or spread throughout the affected organism’s body. It can affect any system. While cats are typically less susceptible to cancer, their risk increases with age, just like people. It often begins with non-diagnostic symptoms, such as loss of appetite, vomiting, or a change in litter box usage.

sick cat covered in blanket lies on the window in winter
Image Credit: Germanova Antonina, Shutterstock

Cancer and Blood Work

The answer to whether a blood test will help a veterinarian diagnose cancer is yes and no. It can help identify diseases that affect the blood, such as lymphoma or leukemia. Both manifest themselves as white blood cell anomalies, although it’s more definitive with the latter. However, there isn’t a single test that can make a concrete cancer diagnosis across the board.

That doesn’t mean that blood work isn’t useful for treating cancer. Instead, these tests can function as a red flag, indicating that something is wrong. For example, several can highlight signs of internal inflammation. A check of a cat’s TK (thymidine kinase) levels could act as a biomarker or indicator of cancer while not explicitly identifying the disease.

Your vet can also test for other chemicals in your cat’s blood, such as calcium. High levels of this mineral are often a sign of a parathyroid gland tumor. If your doctor suspects feline leukemia, they may order an immunofluorescent antibody (IFA) test. Low cholesterol levels or hypocholesterolemia may be a sign of multiple myeloma. These tests provide your vet with more information to identify what’s happening.

However, in many cases, blood tests are another tool that veterinarians use to confirm a suspected cancer diagnosis. Remember that bloodwork often helps a doctor eliminate the reasons for your pet’s symptoms instead of IDing it. Other things a vet may use include X-rays, ultrasound, and fluid analysis. They may also biopsy any abnormal growths.

cat at vet with owner and veternarian
Image Credit: 4 PM production, Shutterstock

The Role of Blood Tests in Cancer Treatment

Blood tests are an excellent way to monitor your cat’s health during cancer treatment. Routine blood work can identify infections, anemia, or allergic reactions. Bear in mind that your pet is susceptible to other diseases in its weakened state. Monitoring your cat’s overall well-being is a vital part of the healing process.

Thankfully, research is ongoing for more effective ways to identify cancer in the early stages when the prognosis is best. Perhaps, one day a test will exist that can be part of your cat’s routine blood work with its annual exam.

Final Thoughts

A cancer diagnosis is a scary prospect for any pet owner. However, it’s essential to remember that it isn’t a death sentence. Many animals recover from this devastating disease and live normal lifespans. While blood tests can’t diagnose all conditions, they can provide your veterinarian with valuable information for treating your cat while monitoring its health as it heals.

Featured Image Credit: SingingMedia, Shutterstock

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