Eosinophil Count (Peripheral Blood)
This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight infections and respond to allergies and inflammation.
["Eosinophils help protect your body from harmful substances and infections, and this test helps doctors assess their levels for health monitoring or diagnosis."]
Key facts at a glance
- LOINC
- 68400-1
- Short code
- Eosinophil # Plr Manual
- Synonyms
- Eosinophil # Plr Manual
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- TAT
- 4–24 hours
- Order
- routine
Why This Test Is Done
Doctors may order this test to diagnose or monitor conditions such as allergies, asthma, parasitic infections, certain cancers (like leukemia), or inflammatory diseases. It can also help evaluate symptoms like persistent coughing, skin rashes, or unexplained weight loss.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm to draw blood. The process usually takes a few minutes, and you can resume normal activities afterward.
What the Results Mean
Results are typically reported as the absolute count of eosinophils per microliter of blood. Elevated levels may indicate allergic reactions, infections, or inflammatory conditions, while very low levels might suggest immune system issues or certain medications.
Common Conditions Linked to Eosinophil Levels
High eosinophil counts can be associated with allergies, asthma, parasitic infections, certain cancers, or autoimmune diseases. Low levels may be linked to immune deficiencies or side effects from medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated eosinophil counts can signal chronic inflammation, allergic responses, or underlying conditions like eosinophilic esophagitis or certain lung diseases. Doctors may recommend further testing or treatment based on the cause. Low eosinophil counts may warrant investigation into immune system disorders or medication effects.
Short name
Eosinophil Blood Test
Frequently asked questions
What causes eosinophils to be high?
What causes eosinophils to be low?
Can diet affect eosinophil levels?
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