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Eosinophil Count in Whole Blood (Manual Differential Count)

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 allergic reactions.

Quick summary

["Eosinophils help your body defend against parasites and allergies, and their levels can signal underlying health conditions."]

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

Key facts at a glance

LOINC
57840-1
Short code
Eosinophil NFr Dial fld Manual
Synonyms
Eosinophil NFr Dial fld Manual
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
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

Doctors may order an eosinophil count to investigate symptoms like persistent itching, skin rashes, asthma, or unexplained weight loss. It can also help diagnose conditions such as allergies, parasitic infections, or certain types of cancer.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. The test involves counting eosinophils under a microscope after staining the blood sample.

How the Results Are Interpreted

Results are reported as the absolute number of eosinophils per microliter of blood. Elevated levels may indicate allergies, infections, or other conditions requiring further evaluation.

Common Conditions Linked to Eosinophil Levels

High eosinophil counts can be linked to allergies, asthma, parasitic infections, or certain autoimmune diseases. Low levels may suggest immune suppression or other blood disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated eosinophil counts can signal allergic reactions, parasitic infections, or inflammatory conditions. Doctors may recommend additional tests to identify the underlying cause, such as allergy testing or imaging studies.

Short name

Eosinophil Count

Frequently asked questions

What causes eosinophil levels to rise?
Eosinophil levels can increase due to allergies, asthma, parasitic infections, certain cancers (like leukemia), or inflammatory conditions. Stress or medications may also temporarily affect counts.
When should I ask my doctor about my eosinophil results?
If your eosinophil count is significantly higher or lower than expected, discuss it with your doctor. They may review your symptoms, medical history, and other test results to guide next steps.
Can diet or supplements affect eosinophil counts?
Dietary changes or supplements may indirectly influence inflammation or immune responses, but they rarely directly alter eosinophil counts. Always consult your doctor before making major changes.
  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