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Eosinophil Count (Peripheral 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 levels can help diagnose infections, allergies, or other conditions affecting your immune system."]

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

Key facts at a glance

LOINC
14344-6
Short code
Eosinophil NFr Plr Manual
Synonyms
Eosinophil NFr Plr Manual
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like persistent cough, skin rashes, digestive issues, or unexplained fatigue. It could also be used to monitor conditions like asthma, allergies, or parasitic infections.

Common Reasons for Testing

Eosinophil counts are often checked when doctors suspect conditions like allergic disorders, parasitic infections, or certain types of inflammatory diseases. High levels may indicate allergies, asthma, or other immune-related issues.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm, and a few drops of blood will be collected into a test tube. The process usually takes just a few minutes.

What to Expect During the Test

The test involves drawing blood from a vein in your arm. You might feel a slight pinch, but it’s generally quick and painless. Most people don’t experience any lasting discomfort afterward.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Eosinophil counts can be elevated in conditions such as allergic reactions, parasitic infections, certain cancers (like Hodgkin lymphoma), or chronic inflammatory diseases. Low levels may suggest immune deficiencies or other underlying health issues.

Short name

Eosinophil Count

Frequently asked questions

How long does it take to get the results?
Results are typically available within 24 to 48 hours, depending on your lab’s processing schedule. Your doctor will discuss the findings with you during your follow-up visit.
What do abnormal eosinophil levels mean?
High eosinophil levels may signal allergies, infections, or other immune-related conditions. Low levels might indicate immune system issues or certain infections. Your doctor will interpret the results in the context of your symptoms and medical history.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it’s a simple blood draw with no dietary restrictions.
  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