Skip to content

Eosinophil Count (Peripheral Blood)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of eosinophils, a type of white blood cell involved in allergic reactions and fighting certain infections.

Quick summary

["Eosinophils help identify allergies, parasitic infections, or inflammatory conditions."]

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

Key facts at a glance

LOINC
58766-7
Short code
Epi Cells #/area Smn HPF
Synonyms
Epi Cells #/area Smn HPF
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-hpf
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

What Are Eosinophils?

Eosinophils are a subtype of white blood cells that play a role in defending the body against parasites, regulating allergic responses, and managing chronic inflammatory diseases. They contain granules filled with enzymes that help neutralize harmful substances.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained infections. It can also help diagnose conditions such as allergies, parasitic infections, or certain autoimmune disorders.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then analyzed under a microscope to count eosinophils. Results are typically reported as the absolute number of eosinophils per microliter of blood.

What Do the Results Mean?

Elevated eosinophil counts may suggest allergic reactions, parasitic infections, or inflammatory conditions. Lower-than-normal counts might indicate certain immune deficiencies or other underlying health issues. Your doctor will interpret results in relation to your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil WBC Count

Frequently asked questions

What are the normal ranges for this test?
Normal ranges can vary slightly between labs, but typically, eosinophil counts range from about 0 to 500 cells per microliter of blood. Your doctor will use these results alongside your clinical picture to guide diagnosis and treatment.
How often should I get this test?
The frequency depends on your symptoms and medical condition. If you have an ongoing issue like allergies or a chronic illness, your doctor may recommend periodic monitoring. Follow their guidance for scheduling.
Can lifestyle changes affect eosinophil levels?
Yes, certain lifestyle factors like diet, stress, and exposure to allergens can influence white blood cell counts, including eosinophils. Maintaining a balanced diet, managing stress, and avoiding known allergens may help stabilize your 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