Unit Converter
Eosinophils (Absolute eosinophil count)
(Marker for Allergy, Asthma, Parasitic Infections & Eosinophilic Disorders)
Synonyms
- Absolute eosinophil count
- AEC
- Eosinophil count
- Blood eosinophils
- Eos count
- Eosinophilia index
Units of Measurement
Common hematology units:
- 10⁹/L
- G/L (Gigaper liter = 10⁹/L)
- Gpt/L (same as G/L)
- cells/L
- 10³/µL
- 1000/µL
- 10³/mm³
- 1000/mm³
- K/µL (“K” = thousand)
- K/mm³
- cells/µL
- cells/mm³
Unit Equivalencies
1) Between SI & Conventional Units
1×109/L=1000 cells/μL=1 K/μL1 \times 10^9/L = 1000\ cells/\mu L = 1\ K/\mu L1×109/L=1000 cells/μL=1 K/μL
2) All conversions
| Unit | Equivalent |
| 1 × 10⁹/L | = 1 G/L = 1 Gpt/L |
| 1 × 10⁹/L | = 1000 cells/µL |
| 1000 cells/µL | = 1000/mm³ = 1 K/µL = 1 K/mm³ |
| 1 cells/µL | = 0.001 × 10⁹/L |
Description
Eosinophils are granulocytic white blood cells involved in:
- Allergic inflammation
- Anti-parasitic defense
- Immune modulation
- Tissue repair
- Asthma pathophysiology
Absolute eosinophil count (AEC) reflects actual number of eosinophils in blood, more meaningful than percentage.
Physiological Role
Eosinophils contain:
- Major basic protein (MBP)
- Eosinophil cationic protein (ECP)
- Eosinophil peroxidase (EPO)
- Cytokines & chemokines
They participate in:
- Helminthic defense
- Allergic reactions
- Inflammatory responses
- Asthma airway remodeling
Clinical Significance
Low AEC (Eosinopenia)
Less clinically important.
Occurs in:
- Acute infection
- Sepsis
- Cushing syndrome / high cortisol
- Stress response
- After glucocorticoids
Usually transient and benign.
High AEC (Eosinophilia)
(Most important clinically)
Classification
| AEC (cells/µL) | Severity |
| <500 | Normal |
| 500–1500 | Mild eosinophilia |
| 1500–5000 | Moderate eosinophilia |
| >5000 | Severe eosinophilia |
| ≥1500 for >6 months | Hypereosinophilia (HES) |
Causes of Elevated Eosinophils
1. Allergic Diseases
- Asthma
- Allergic rhinitis
- Atopic dermatitis
- Drug allergies
- Food allergy
2. Parasitic / Helminthic Infections
High AEC strongly suggests parasites such as:
- Strongyloides
- Hookworm
- Ascaris
- Schistosomiasis
- Filariasis
3. Hypereosinophilic Syndrome (HES)
AEC >1500 cells/µL persistently, with organ involvement.
4. Autoimmune & Vasculitic Disorders
- EGPA (Churg–Strauss)
- Eosinophilic fasciitis
- Sarcoidosis
5. Skin Diseases
- Pemphigus
- Bullous dermatoses
- Urticaria
6. Malignancy
- Hodgkin lymphoma
- T-cell lymphomas
- Solid tumors (rare)
7. Endocrine Causes
- Adrenal insufficiency
- Autoimmune adrenalitis
8. Infections (Non-parasitic)
- Fungal (aspergillosis)
- COVID-associated eosinophilia (rare)
Reference Intervals
(Tietz 8E + Hematology Standards + Mayo + ARUP)
Adults & Children
- Absolute eosinophil count: 0 – 500 cells/µL
Equivalent to: - 0 – 0.5 ×10⁹/L
- 0 – 0.5 K/µL
Normal Diurnal Variation
- Lowest: morning
- Highest: evening
(Shifted by cortisol rhythm)
Units Description Summary
All Units Mapped
| Units | Description |
| 10⁹/L, G/L, Gpt/L | SI units (gigacells per L) |
| cells/µL, K/µL | US/hematology units |
| 10³/mm³, 1000/mm³ | Same as cells/µL |
| µL vs mm³ | Numerically identical |
Key Conversion
1×109/L=1000 cells/µL=1 K/µL1 \times 10^9/L = 1000\ \text{cells/µL} = 1\ \text{K/µL}1×109/L=1000 cells/µL=1 K/µL
Diagnostic Uses
1. Allergy & Asthma
- Elevated AEC supports type 2 (eosinophilic) asthma
- Helps guide biologic therapy decisions (anti–IL-5, anti–IL-4R)
2. Parasitic Infection Workup
One of the strongest clues for helminthic disease.
3. Atopic Dermatitis & Urticaria
AEC correlates with severity.
4. Hypereosinophilic Syndrome
AEC ≥1500 cells/µL + organ involvement.
5. Autoimmune Vasculitis
- EGPA
- Eosinophilic pneumonia
6. Drug Hypersensitivity
- DRESS syndrome
- Drug-induced eosinophilia
Analytical Notes
- Measured on automated hematology analyzers
- Absolute count is more reliable than percentage
- Repeat test recommended if borderline elevated
- Corticosteroids rapidly suppress eosinophils
- Consider timing (diurnal variation)
Clinical Pearls
- AEC >1500 cells/µL for >6 months → hypereosinophilia, evaluate organs (heart, lungs, GI).
- Normal eosinophils do NOT exclude allergic disease - ECP sometimes more sensitive.
- Parasites, allergies, and drug reactions together account for >90% of eosinophilia.
- Always check stool ova & parasite, IgE, and chest imaging for unexplained eosinophilia.
Interesting Fact
Eosinophils were named for their affinity to eosin dye, staining bright orange-pink due to granule proteins like major basic protein (MBP).
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Hematology.
- AAAAI/WAO Allergy Guidelines - Eosinophils in Atopy & Asthma.
- Mayo Clinic Laboratories - Eosinophil Count.
- ARUP Consult - Eosinophilia Evaluation.
- WHO Hematology Standards.
- MedlinePlus / NIH - Eosinophils.