Eosinophil Count (Peripheral Blood)

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It can also help diagnose conditions such as parasitic infections, certain types of cancer, or allergic reactions that don’t respond to usual treatments.

What to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your vein (usually in your arm) to draw blood. The process is quick and usually painless. You may feel a brief pinch or slight discomfort, but it won’t take long.

What the Results Mean

Eosinophil counts are typically reported as a percentage of your total white blood cell count or as an absolute number (cells per microliter). High levels may suggest allergic reactions, infections, or other conditions. Low levels might indicate certain immune system issues or medications that suppress white blood cells.

Common Conditions Linked to Eosinophil Levels

Elevated eosinophil counts can be linked to conditions like asthma, allergic reactions, parasitic infections, certain cancers (e.g., lymphoma), or autoimmune diseases. Low eosinophil counts may be seen in conditions like severe infections, certain blood disorders, or after treatments that suppress the immune system.