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Eosinophil Count (Blood)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to inflammation.

Quick summary

["Eosinophil blood tests help doctors understand immune responses and potential allergies or infections."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
711-2
Short code
Eosinophil # Bld Auto
Synonyms
Eosinophil # Bld Auto
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
automated-count
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be used to check for conditions like parasitic infections, certain cancers, or inflammatory diseases.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. The process usually takes a few minutes, and you may feel a slight pinch.

What the Test Results Mean

Results are typically reported as the number of eosinophils per microliter (µL) of blood. High levels may indicate allergies, infections, or other immune-related conditions. Low levels might suggest certain immune deficiencies or chronic diseases.

Common Conditions Linked to Eosinophil Levels

Elevated eosinophil counts can be linked to allergies, asthma, parasitic infections, certain cancers (like leukemia), or autoimmune diseases. Low counts may be associated with immune disorders or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Elevated eosinophils often signal chronic inflammation or allergic reactions, while persistently low levels may warrant further investigation into immune system dysfunction or underlying health conditions.

Short name

Eosinophil Blood

Frequently asked questions

What causes eosinophils to be high?
High eosinophil counts can result from allergies, asthma, parasitic infections, certain cancers, or inflammatory conditions. Stress, certain medications, or autoimmune diseases may also play a role.
What does it mean if my eosinophil count is normal?
A normal eosinophil count doesn’t rule out all causes of symptoms like allergies or infections. Your doctor may still recommend further testing if you have ongoing concerns or symptoms.
Can diet affect eosinophil levels?
Diet alone rarely affects eosinophil levels, but certain foods or allergens may trigger allergic reactions that indirectly influence immune responses. Always follow your doctor’s advice regarding dietary changes.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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