Skip to content

Eosinophil count (per microliter of whole 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 allergic reactions.

Quick summary

["Eosinophil counts can help diagnose or monitor conditions like allergies, asthma, or certain infections."]

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

Key facts at a glance

LOINC
80676-0
Short code
EC O157 rfbE gene Stl Ql NAA+probe
Synonyms
EC O157 rfbE gene Stl Ql NAA+probe
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
CPT
86430
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

What Are Eosinophils?

Eosinophils are a type of white blood cell that play a key role in defending the body against parasites and managing allergic responses. They also help regulate inflammation. When your body detects an infection or allergy, eosinophil levels may rise to support the immune response.

Why Might You Need This Test?

Your doctor may order an eosinophil count to investigate symptoms such as persistent itching, skin rashes, asthma, or unexplained fevers. It can also help diagnose conditions like eosinophilic esophagitis, certain infections (e.g., parasitic), or autoimmune disorders.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of eosinophils present.

What Do Results Mean?

Results are reported as the number of eosinophils per microliter of blood. Elevated levels may indicate an allergic reaction, infection, or other immune-related conditions. Lower-than-expected levels might suggest certain immune deficiencies or chronic illnesses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance:

Short name

Eosinophil CBC

Frequently asked questions

Why do I need this test?
Your doctor may recommend this test to check for underlying causes of symptoms like persistent itching, unexplained weight loss, or chronic sinus issues. It can also help guide treatment for known conditions like allergies or parasitic infections.
What if my results are high?
High eosinophil counts may signal conditions like asthma, allergies, or parasitic infections. Your doctor will discuss next steps, which could include further testing or treatment adjustments.
How often should I get this test?
Frequency depends on your health status and treatment plan. Follow your doctor’s advice—this test may be part of routine monitoring for certain conditions or performed as needed for symptoms.
  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