Calculate your AEC
Lab calculation aid — not medical advice. The severity band describes the lab value only; it is not a diagnosis. Discuss any abnormal result with your clinician.
Worked example
Input: WBC 8.0 ×109/L, eosinophils 5%
- Convert the percentage to a fraction: 5 ÷ 100 = 0.05
- Multiply by the WBC count: 8.0 × 0.05 = 0.40 ×109/L
- Convert units: 0.40 × 1,000 = 400 cells/µL
- Band check: 0.40 < 0.5 → normal
Same arithmetic as a clinical laboratory: the percentage of eosinophils multiplied by the white blood cell count.
AEC reference bands
| Band | Absolute eosinophil count |
|---|---|
| Normal | < 0.5 ×109/L (< 500 cells/µL) |
| Mild eosinophilia | 0.5–1.5 ×109/L (500–1,500 cells/µL) |
| Moderate eosinophilia | 1.5–5.0 ×109/L (1,500–5,000 cells/µL) |
| Severe eosinophilia | > 5.0 ×109/L (> 5,000 cells/µL) |
Bands per the clinical review “Eosinophilia and Hypereosinophilia: A Practical Approach” (European Journal of Haematology), the MSD Manual (Professional Edition), and the review “Approach to Patients with Eosinophilia” (PMC). Exact cutoffs 0.5 / 1.5 / 5.0 belong to the upper band (0.5 = mild, 1.5 = moderate, 5.0 = severe). Reference ranges vary slightly by laboratory.
Boundary: this is a lab calculation tool, not an eosinophilia diagnosis tool. The bands label the number only; clinical meaning depends on persistence, symptoms, and further testing decided by a clinician.
The formula & units
AEC = WBCtotal × (eosinophil% ÷ 100)
The percentage and the WBC count must be in consistent units. Two unit systems are in common use:
- ×109/L (SI) — e.g. 8.0
- cells/µL (conventional) — e.g. 8,000
1 ×109/L = 1,000 cells/µL
So 0.40 ×109/L = 400 cells/µL, and 500 cells/µL = 0.50 ×109/L. This calculator accepts either WBC unit and always reports both AEC units.