Diagnosis of eosinophilia typically involves a complete blood count (CBC), which measures the levels of various blood cells, including eosinophils. A normal eosinophil count is usually less than 500 cells per microliter of blood. Eosinophilia is generally defined as an eosinophil count greater than 500 cells per microliter. Further investigation may include allergy testing, stool samples for parasites, and imaging studies to identify underlying causes.
