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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 infections caused by parasites and play a role in allergic reactions.

Quick summary

["Eosinophil counts help diagnose and monitor conditions affecting your immune system or allergies."]

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

Key facts at a glance

LOINC
20472-7
Short code
Eosinophil Spec Ql Wright Stn
Synonyms
Eosinophil Spec Ql Wright Stn
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
wright-stain
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

Why This Test Is Done

Your healthcare provider may order this test to check for 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 to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your arm or hand to draw blood. The process is quick and usually painless. If you’re nervous, let your healthcare provider know so they can help make it more comfortable.

What the Results Mean

Eosinophil counts can vary based on your overall health, age, and medical conditions. High levels may suggest allergies, infections, or inflammatory diseases, while very low levels might indicate immune system issues or certain medications.

Common Conditions Linked to Eosinophil Levels

Elevated eosinophil counts are often linked to conditions like allergic reactions, asthma, parasitic infections, or certain cancers (e.g., lymphoma). Low levels may be associated with autoimmune diseases or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil Test

Frequently asked questions

What causes my eosinophil count to be high?
High eosinophil counts can result from allergies, asthma, parasitic infections, or inflammatory conditions. Some medications, like certain asthma inhalers or blood pressure drugs, may also temporarily raise levels. If you notice persistent symptoms, discuss them with your doctor.
Can low eosinophil counts be dangerous?
Very low eosinophil counts are less common but may indicate immune system dysfunction, certain medications, or underlying health issues. Your doctor will review your full medical picture to determine if further testing or adjustments are needed.
How often should I get this test?
The frequency depends on your condition. If you have a known allergy, asthma, or other chronic condition, your doctor may recommend regular monitoring. If this test is part of routine check-ups, they’ll let you know how often it’s needed.
  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