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Eosinophil count (per microliter of whole 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

["Eosinophils help protect against parasites and allergic reactions, but elevated levels may signal underlying conditions."]

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

Key facts at a glance

LOINC
43432-4
Short code
E coli K1 Ag Ur Ql
Synonyms
E coli K1 Ag Ur Ql
Category
chemistry
Sample
urine
Container
Sterile urine container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
10 mL
Stability
Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
0
Lipemia max
0
Icterus max
0
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, allergens, and some infections. They release chemicals to combat these threats and help reduce inflammation. While they are usually present in small amounts, they can increase in response to specific conditions.

Why Might Your Eosinophil Count Be Checked?

Your doctor may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained weight loss. It can also be used to monitor conditions like allergies, asthma, parasitic infections, or certain cancers.

Common Conditions Affecting Eosinophil Levels

Elevated eosinophil counts may indicate conditions such as allergic reactions, asthma, parasitic infections, certain types of cancer (like Hodgkin lymphoma), or autoimmune disorders. Low levels might suggest infections, stress, or certain medications.

How Is This Test Performed?

A small blood sample is drawn from a vein in your arm. The sample is then analyzed in a lab to count the number of eosinophils present in your blood.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Eosinophils are typically present in small numbers in healthy individuals. When they rise above normal levels, it often signals an ongoing immune response to allergens, parasites, or other triggers. Conversely, very low levels may suggest immune suppression or certain infections. This test helps healthcare providers diagnose and manage conditions like asthma, eosinophilic esophagitis, or parasitic infections.

Short name

Eosinophil blood count

Frequently asked questions

What does an abnormal eosinophil count mean?
An elevated eosinophil count may point to allergic reactions, asthma, parasitic infections, or certain autoimmune or inflammatory conditions. A low count could be due to stress, infections, or certain medications. Your doctor will discuss the results in the context of your symptoms and medical history.
How long does it take to get results from this test?
Results from this test are usually available within 1 to 3 business days, depending on your lab’s processing time. Your healthcare provider will contact you once the results are ready.
Can lifestyle changes affect eosinophil levels?
Yes, certain lifestyle factors like stress, diet, or exposure to allergens may influence eosinophil counts. Avoiding known triggers (like certain foods or environmental allergens) and managing stress through healthy habits can sometimes help stabilize levels. Always follow your doctor’s advice based on your specific situation.
  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