What Are Eosinophils in a Blood Test?

Q: What Are Eosinophils in a Blood Test?

Eosinophils: WBCs that fight parasites and cause allergic inflammation. High eosinophils = allergies, asthma, parasitic infection, or drug reaction.

Eosinophils are white blood cells that fight parasites and participate in allergic responses. They comprise 1–4% of WBCs.

Normal Range

1–4% of WBC
Absolute: 50–500/µL

High Eosinophils (Eosinophilia)

Allergic conditions: asthma, hay fever, eczema
Parasitic infection
Drug reactions
Autoimmune disease
Eosinophilic esophagitis
Hypereosinophilic syndrome (rare, serious)

Severity

Mild: 500–1,500/µL
Moderate: 1,500–5,000/µL
Severe: above 5,000/µL (organ damage risk)

Source: NLM MedlinePlus, American Association for Clinical Chemistry.

Ratings summarize government-reported measures — they don't capture your personal needs. Visit the facility, ask about staffing and services, and use CMS checklists. This profile is informational only and is not a recommendation.

Compare lab testing options near you ↗ (affiliate link)