Eosinophil count (per microliter of whole blood)
This test measures the number of eosinophils, a type of white blood cell involved in allergic reactions and fighting parasites. Eosinophils help protect the body from infections and respond to inflammation.
["Eosinophils help fight infections and allergic reactions, and their count can signal underlying health conditions."]
Key facts at a glance
- LOINC
- 49839-4
- Short code
- Eosinophil UrnS Ql Wright Stn
- Synonyms
- Eosinophil UrnS Ql Wright Stn
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- wright-stain
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why is this test done?
Doctors may order an eosinophil count to diagnose or monitor conditions such as allergies, asthma, parasitic infections, certain cancers (like leukemia), or autoimmune diseases. It can also help assess how your body is responding to treatments for these conditions.
What does a high or low eosinophil count mean?
Elevated eosinophil levels may indicate allergic reactions, asthma, parasitic infections, or conditions like eosinophilic esophagitis or certain cancers. Low levels might suggest immune suppression, severe infections, or other systemic conditions. Your doctor will interpret results in the context of your symptoms and medical history.
How is this test performed?
A blood sample is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the number of eosinophils among your white blood cells. The result is expressed as the number of eosinophils per microliter of blood.
What should you do before the test?
No special preparation is needed for this test. However, if you are taking medications that affect your immune system (such as steroids), let your healthcare provider know before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Eosinophils play a key role in defending against parasites and managing allergic responses. Abnormal levels can signal conditions requiring further evaluation, such as chronic inflammation, immune disorders, or certain cancers. Your doctor will use the results alongside other information to guide diagnosis and treatment.
Short name
Eosinophil WBC count
Frequently asked questions
Can I eat or drink before this test?
How long will it take to get my results?
Does this test hurt?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy