Eosinophil count (peripheral blood)
This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight infections caused by parasites and play a role in allergic reactions.
["Eosinophils help your body defend against certain infections and allergies."]
Key facts at a glance
- LOINC
- 105797-5
- Short code
- S epidermidis DNA Ct Bld +Qn NAA+prob
- Synonyms
- S epidermidis DNA Ct Bld +Qn NAA+prob
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- probe-amp-tar
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Are Eosinophils?
Eosinophils are a type of white blood cell that helps your body respond to infections and allergic reactions. They are named for their distinctive red granules (eosinophils) under a microscope. These cells are part of your immune system and can increase in response to certain conditions, such as allergies, asthma, or parasitic infections.
Why Might You Need This Test?
Your doctor may order an eosinophil count to investigate symptoms like persistent itching, skin rashes, asthma, chronic sinusitis, or unexplained weight loss. It can also help diagnose conditions such as allergies, parasitic infections, certain cancers (like leukemia), or autoimmune diseases.
How Is the Test Performed?
A blood sample is taken from a vein, usually in your arm. The blood is then analyzed in a lab to count the number of eosinophils. This test is typically done as part of a complete blood count (CBC).
What Do Results Mean?
Results are usually reported as a count of eosinophils per microliter (µL) of blood. High eosinophil counts may suggest allergies, infections, or other conditions affecting your immune system. Low counts may indicate certain infections, immune disorders, or other health issues.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Eosinophils serve as markers for specific immune responses. Elevated levels can signal allergic reactions, parasitic infections, or inflammatory conditions, while low levels may indicate immune suppression or other systemic issues. Your doctor will interpret results in the context of your symptoms and medical history.
Short name
Eosinophil CBC
Frequently asked questions
What causes an elevated eosinophil count?
What causes a low eosinophil count?
How often should I get this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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