Eosinophil count in serum/plasma (absolute)

Why Might This Test Be Done?

Your healthcare provider may order this test to evaluate symptoms such as persistent itching, skin rashes, asthma, or chronic sinusitis. It can also help diagnose conditions like allergies, parasitic infections, certain cancers (e.g., leukemia), or autoimmune disorders. Sometimes, elevated eosinophil counts are checked alongside other blood tests to identify the root cause of unexplained symptoms.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into your arm to draw blood. If you’re concerned about pain or discomfort, let your provider know. If you’re on blood-thinning medications, inform your healthcare team beforehand.

What the Test Results Mean

Eosinophil counts are typically reported as a number of cells per microliter (cells/µL). While reference ranges vary by lab, elevated levels (above normal) may indicate allergies, infections, or inflammatory conditions. Very low levels might suggest immune system issues or certain blood disorders. Always discuss your results with your doctor.

Common Conditions Linked to Eosinophil Levels

High eosinophil counts can be linked to conditions like asthma, eosinophilic esophagitis, certain types of leukemia, parasitic infections, or allergic reactions. Low levels may be associated with immune deficiencies or other blood disorders. Your provider will consider your full medical history and symptoms to interpret results accurately.