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Absolute count of eosinophils (per microliter of 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 levels can signal allergic reactions, infections, or other immune responses."]

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

Key facts at a glance

LOINC
35060-3
Short code
Eosinophil # Snv
Synonyms
Eosinophil # Snv
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Are Eosinophils?

Eosinophils are a type of white blood cell that play a role in defending against parasites and managing allergic reactions. They also help reduce inflammation in some conditions. While they’re usually present in small amounts, elevated levels may indicate specific health concerns.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained fatigue. It can also help diagnose conditions like allergic reactions, parasitic infections, or certain autoimmune disorders.

Common Reasons for Testing

Common reasons include suspected allergies, chronic sinusitis, asthma, or conditions like eosinophilic esophagitis. It may also be checked during evaluations for unexplained skin rashes, lung issues, or other inflammatory conditions.

What to Expect Before the Test

No special preparation is needed. A simple blood draw from your arm is all that’s required. The test is quick and typically done in a lab setting.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil count

Frequently asked questions

How do eosinophil levels affect health?
Elevated eosinophil counts (above normal) may signal allergic reactions, parasitic infections, or certain inflammatory or autoimmune conditions. Very low levels might indicate immune system dysfunction or other underlying issues. Always discuss results with your healthcare provider.
What does a high eosinophil count mean?
A high eosinophil count can suggest conditions like asthma, allergies, parasitic infections, or certain cancers (e.g., eosinophilic leukemia). Your doctor will consider your symptoms and other test results to determine the cause.
Can low eosinophil counts be dangerous?
Low eosinophil counts are less common but may indicate immune deficiencies or certain medications that suppress white blood cell production. If you notice unusual symptoms like frequent infections, talk to your doctor about further evaluation.
  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