Eosinophil Count 0.3%: What It Means in a CBC

In a standard complete blood count (CBC) with differential, the normal eosinophil percentage is 0.0%–0.5% (or absolute count <500 cells/µL). A result of 0.3% falls well within the normal range, indicating a typical immune response.

Context

• Eosinophils combat parasites and mediate allergic inflammation.
• Mild elevations (0.5–5%) occur with allergies, asthma, eczema, drug reactions, helminth infections.
• Marked eosinophilia (>1.5×10⁹/L or >15%) warrants investigation for eosinophilic disorders, malignancy, or rare infections.

When to Discuss with Your Doctor

• If you have symptoms (wheezing, rash, GI issues, travel to endemic areas).
• If absolute eosinophil count is elevated despite normal percentage (e.g., high total WBC).
• For persistent unexplained eosinophilia.

Reference: Mayo Clinic – Eosinophilia