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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 allergies or inflammation.

Quick summary

["Eosinophils 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
27416-7
Short code
ENA Scl70 Ab Ser-aCnc
Synonyms
ENA Scl70 Ab Ser-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Are Eosinophils?

Eosinophils are a type of white blood cell that play a role in defending the body against parasites, allergies, and some chronic inflammatory conditions. They release chemicals that help fight off harmful organisms and regulate immune responses.

Why Might This Test Be Ordered?

Your doctor may order this test to investigate symptoms like persistent itching, skin rashes, asthma, or unexplained fatigue. It can also help diagnose conditions such as allergic reactions, parasitic infections, or certain autoimmune diseases.

When Might You Need This Test?

You might need this test if you have symptoms like persistent itching, unexplained skin rashes, asthma, or if you’re being evaluated for conditions like eosinophilic esophagitis, allergic disorders, or parasitic infections.

What Does a High or Low Level Mean?

Elevated eosinophil counts may indicate allergies, asthma, parasitic infections, or certain inflammatory or autoimmune conditions. Low levels might suggest immune suppression or other underlying health issues, though this is less common.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Eosinophils are often elevated in allergic reactions, parasitic infections, asthma, and certain chronic inflammatory diseases. They can also be elevated in conditions like eosinophilic esophagitis or certain cancers. Low eosinophil counts are less frequently associated with clinical significance but may indicate immune dysfunction or other systemic conditions.

Short name

Eosinophil blood level

Frequently asked questions

What does an elevated eosinophil count mean?
An elevated eosinophil count can signal an allergic reaction, parasitic infection, asthma, or another inflammatory condition. Your doctor will consider your symptoms and other test results to determine the cause.
How is this test performed?
This test involves drawing blood from a vein in your arm. The blood sample is then analyzed in a lab to count the number of eosinophils present. The process is quick and typically requires no special preparation.
Do I need to prepare for this test?
No special preparation is needed for this blood test. You may have some mild discomfort from the needle, but it usually goes away quickly. If you’re on blood-thinning medication, let your doctor know before the test.
  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