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Eosinophil count (per microliter) in serum/plasma

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 infections and respond to allergies and inflammation.

Quick summary

["Eosinophils help protect your body but can become too high in certain health conditions."]

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

Key facts at a glance

LOINC
63400-6
Short code
ENA Scl70 Ab CSF IA-aCnc
Synonyms
ENA Scl70 Ab CSF IA-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
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 control inflammation. When your body detects an infection or allergy, eosinophils increase to fight the problem.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like persistent itching, skin rashes, asthma, or digestive issues that could indicate allergies, infections, or other conditions affecting eosinophil levels.

Common Conditions Linked to Eosinophil Levels

High eosinophil counts may suggest conditions like allergies, asthma, parasitic infections, certain autoimmune diseases, or blood disorders. Low levels might indicate stress, infections, or other immune system changes.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to count eosinophils using a specialized blood test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil Blood Test

Frequently asked questions

What does an abnormal eosinophil count mean?
An elevated eosinophil count (above normal) may signal allergies, infections, or inflammatory conditions. A low count might indicate stress, recent illness, or other immune-related factors. Your doctor will discuss results in the context of your symptoms and medical history.
How often should I get this test?
Your doctor will determine how often to check your eosinophil count based on your health needs, symptoms, or ongoing treatment. Follow-up tests may be scheduled if you have conditions like asthma, allergies, or blood disorders.
Can lifestyle changes affect eosinophil levels?
Yes, factors like stress, diet, exercise, and exposure to allergens can influence eosinophil counts. Managing allergies, avoiding triggers, and maintaining overall health may help stabilize your levels.
  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