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Eosinophil count (absolute)

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 counts help doctors assess immune responses and identify potential allergies or infections."]

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

Key facts at a glance

LOINC
26449-9
Short code
Eosinophil # Bld
Synonyms
Eosinophil # Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 is this test done?

Your doctor may order this test to diagnose or monitor conditions like allergies, asthma, parasitic infections, or certain types of cancer. It can also help evaluate symptoms such as persistent itching, skin rashes, or unexplained fatigue.

What does a high eosinophil count mean?

Elevated eosinophil levels often point to allergic reactions, parasitic infections, or inflammatory conditions. Very high counts may suggest conditions like asthma, certain cancers, or autoimmune disorders.

What does a low eosinophil count mean?

Low eosinophil counts may occur with certain infections (e.g., viral infections), immune deficiencies, or long-term use of certain medications. They can also be seen in chronic illnesses like HIV or severe burns.

How is this test performed?

A small blood sample is drawn from a vein, typically in your arm. The sample is then analyzed in a lab to count the number of eosinophils among your white blood cells.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Eosinophils play a key role in defending against parasites and managing allergic responses. Abnormal counts can signal underlying health issues requiring further evaluation, such as chronic inflammation, infections, or immune disorders.

Short name

Eosinophil blood count

Frequently asked questions

What are the typical reference ranges?
Reference ranges vary by lab and age. Generally, healthy adults have eosinophil counts between 0.04% and 0.5% of total white blood cells, though values can differ.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms, medical history, and treatment plan. Follow-up tests may be needed if you have ongoing conditions like allergies or asthma.
Can lifestyle changes affect eosinophil levels?
Yes, stress, certain medications (e.g., steroids), or chronic conditions may influence eosinophil counts. Discuss any changes in your routine with your healthcare provider.
  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