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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 and respond to allergies and inflammation.

Quick summary

["Eosinophil levels can signal allergic reactions, infections, or other immune responses."]

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

Key facts at a glance

LOINC
14125-9
Short code
E histolyt Stl Ql Tri Stn
Synonyms
E histolyt Stl Ql Tri Stn
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
trichrome-stain
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be used to check for conditions like parasitic infections, certain cancers, or autoimmune disorders.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. It usually takes a few minutes, and you may feel a brief pinch. If you’re on blood thinners, let your doctor know before the test.

What to Expect During the Test

The blood sample is sent to a lab where it’s analyzed to count eosinophils. Results are typically ready within a few days.

Possible Results and Next Steps

Higher-than-normal eosinophil counts may indicate allergies, infections, or inflammatory conditions. Lower-than-normal counts might suggest immune suppression or certain blood disorders. Your doctor will discuss results with you and decide if further testing or treatment is needed.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil

Frequently asked questions

What causes eosinophils to rise?
Eosinophil levels can increase due to allergies, asthma, parasitic infections, certain cancers (like leukemia), or autoimmune diseases. Chronic conditions like inflammatory bowel disease may also be associated with elevated counts.
Can low eosinophil counts be dangerous?
Low eosinophil counts are less common but can occur with certain blood disorders, immune deficiencies, or after treatments that suppress the immune system. It’s important to discuss symptoms with your doctor, as this may require further evaluation.
How often should I get this test?
This test is usually ordered as needed, depending on your symptoms or medical condition. Your doctor will determine how often it’s recommended for you.
  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