Skip to content

Eosinophil count (absolute)

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 and infections."]

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

Key facts at a glance

LOINC
20822-3
Short code
E coli K99 TSMI Ql IF
Synonyms
E coli K99 TSMI Ql IF
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
if
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 Might Be Ordered

Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be done to check for conditions like parasitic infections, certain cancers, or inflammatory diseases.

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 to draw blood, which usually takes a few minutes. If you’re nervous, let your provider know—they can help make it more comfortable.

What the Results Mean

Eosinophil counts can vary based on health, diet, and recent infections. High levels may suggest allergies, infections, or autoimmune conditions, while very low levels might indicate immune system issues or certain medications.

Common Conditions Linked to Eosinophil Counts

Elevated eosinophils are often seen in allergic reactions, asthma, parasitic infections, or certain cancers (like Hodgkin lymphoma). Low counts may be linked to immune deficiencies or long-term steroid use.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Eosinophils play a key role in defending against parasites and managing allergic responses, but their exact role in chronic diseases like asthma or autoimmune disorders is still being studied. Always discuss your results with your provider for personalized insights.

Short name

Eosinophil blood count

Frequently asked questions

Can I eat or drink before this test?
You can eat and drink normally unless your provider gives specific instructions. This test only requires a blood sample, so fasting isn’t necessary.
How long will I need to wait for my results?
Results are typically available within a few days to a week, depending on your lab’s process. Your provider will contact you once they’re ready to share them with you.
Are there any risks or side effects from this test?
Most people experience only minor discomfort or a slight bruise at the injection site. Rarely, there may be a small risk of infection or excessive bleeding, but these are uncommon.
  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