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Eosinophil Count (Manual Differential Blood 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 allergies and inflammation.

Quick summary

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

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

Key facts at a glance

LOINC
9727-9
Short code
Eosinophil NFr Nose Manual
Synonyms
Eosinophil NFr Nose 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 this test to diagnose or monitor conditions like allergies, asthma, parasitic infections, certain cancers (e.g., leukemia), or autoimmune disorders. It can also help assess how your body is responding to treatments for these conditions.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. The process usually takes a few minutes, and you may feel a brief pinch or discomfort.

What the Test Results Mean

Eosinophil counts are not typically reported with a specific range in every lab, as they vary by age, health, and other factors. 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 eosinophils can be linked to conditions like allergic reactions, asthma, parasitic infections, or certain types of cancer. Low eosinophil counts may be associated with immune deficiencies or side effects from medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil Blood Test

Frequently asked questions

How long will it take to get my results?
Results are usually available within 1–3 business days, depending on your lab. Follow-up with your healthcare provider to discuss the findings.
Can I eat or drink before this test?
No special diet or fasting is required. You can eat and drink normally before your blood draw.
Is there any risk or side effect from this test?
The most common side effect is a slight bruise, redness, or minor pain at the injection site. Rarely, there may be a small risk of infection or allergic reaction to the blood draw process.
  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