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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 certain infections and respond to allergies.

Quick summary

["Eosinophil counts help diagnose and monitor conditions affecting these immune cells."]

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

Key facts at a glance

LOINC
60520-4
Short code
Eosinophil Fld Ql Micro
Synonyms
Eosinophil Fld Ql Micro
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
microscopy-light
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 allergic reactions, 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, similar to other blood tests. The process takes about 5 minutes.

What the Results Mean

Elevated eosinophil counts may indicate allergies, infections, or inflammatory conditions. Lower-than-normal counts could suggest immune system issues or certain blood disorders. Your doctor will interpret results in the context of your overall health and symptoms.

Common Conditions Linked to Eosinophil Counts

High eosinophil counts are often seen in allergic diseases (e.g., asthma, eczema), parasitic infections, or conditions like hypereosinophilic syndrome. Low counts may be linked to immune deficiencies or rare blood disorders.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Eosinophils play a key role in defending against parasites and managing allergic responses. They release chemicals that can cause inflammation, which is why their levels are monitored in conditions affecting the immune system.

Short name

Eosinophil Count

Frequently asked questions

What causes eosinophil counts to rise?
Elevated eosinophil counts can result from allergies, asthma, parasitic infections, certain cancers (e.g., leukemia), or inflammatory diseases. Stress or certain medications may also temporarily affect levels.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times. Your doctor will discuss them with you during your follow-up visit.
Can diet or exercise affect eosinophil counts?
Dietary changes or exercise alone rarely impact eosinophil counts significantly. However, if you suspect food allergies or dietary triggers, discuss them with your doctor before interpreting results.
  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