What Level of Eosinophils Indicates Cancer?

Getting abnormal results on a blood test can be concerning. If you’ve had one and learned you have elevated levels of cells called eosinophils, you might wonder what that means for your health. You might also have heard that elevated eosinophil levels (a condition known as eosinophilia) may be associated with cancer.

This article explains what eosinophils are, what constitutes an abnormally high eosinophil count, what can cause eosinophilia and what to do if your count is high.

What Are Eosinophils?

Eosinophils are white blood cells. They are part of the immune system, defending the body against invading organisms and particles. This includes things like parasites and allergens. Eosinophils contain small granules that release a toxic substance to destroy the invaders.

An eosinophil count of 30 to 350 cells per microliter of blood is considered normal. A count is elevated at 500 cells or more per microliter. This is called eosinophilia, and it falls into three levels of severity based on the cell count:

• 500 to 1,500 is mild eosinophilia
• 1,500 to 5,000 is moderate eosinophilia
• Over 5,000 is severe eosinophilia

What Causes an Elevated Eosinophil Count?

Many conditions besides cancer can cause an elevated eosinophil level. In fact, some of the most common reasons for eosinophilia include:

Allergic Reactions

Conditions like asthma, hay fever, eczema and reactions to specific medications can cause an increase in eosinophils.

Parasitic Infections

Eosinophils are essential for defending the body from parasites. If you have an active infection, your eosinophil count may be elevated.

Some inflammatory conditions can also cause eosinophilia.

Understanding the Link Between Eosinophils and Cancer

While allergies and parasitic infections are the most common causes of eosinophilia, elevated eosinophil levels can be associated with certain types of cancer. That connection is complicated, and it’s crucial to understand that a high eosinophil level alone does not mean you have cancer.

Eosinophilia is more common in blood cancers, including certain types of leukemia, Hodgkin lymphoma and some non-Hodgkin lymphomas. The increase in eosinophils might be a direct result of the cancer affecting the bone marrow, where blood cells are produced, or it might be due to an immune system response to the cancer.

Eosinophilia can also occasionally occur with other cancers, including breast, lung, colon and ovarian cancer.

High Eosinophils Don’t Necessarily Indicate Cancer

It’s worth repeating that while eosinophilia is something your healthcare provider will investigate, a high level doesn’t mean you have cancer. If your count is elevated, your provider will review your medical history, symptoms and test results to determine why that is the case. They may order additional tests for infections, allergies or other inflammatory conditions.

So, while there’s a known connection between elevated eosinophil levels and certain cancers, high eosinophils are not a definitive marker for the disease. Many other, more common conditions can cause eosinophilia.

If you have questions about your eosinophil count, talk with your healthcare provider. They can explain what the result means and how they’ll determine the cause. If you got your test result from another healthcare organization and want to find a Baptist Health provider, you can use our online directory.

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