Eosinophil count (peripheral blood)
This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to allergic reactions.
["Eosinophil levels can help diagnose or monitor conditions affecting your immune system or allergies."]
Key facts at a glance
- LOINC
- 35061-1
- Short code
- Eosinophil # Prt
- Synonyms
- Eosinophil # Prt
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
Your doctor may order this test to check for conditions like allergies, asthma, parasitic infections, or certain types of cancer. It can also help evaluate symptoms such as persistent itching, skin rashes, or unexplained fatigue.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm, and a few drops of blood will be drawn into a test tube or vial. The process usually takes just a few minutes.
What the Results Mean
Elevated eosinophil levels may indicate an allergic reaction, parasitic infection, or certain inflammatory or autoimmune conditions. Lower-than-normal levels might suggest stress, certain infections, or other health issues. Your doctor will interpret results in the context of your overall health and symptoms.
Common Conditions Monitored
Eosinophil counts are often checked in people with suspected allergies, asthma, eosinophilic esophagitis, or conditions like Crohn’s disease or certain types of leukemia.
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. High levels can signal chronic inflammation or immune-related disorders, while low levels may reflect acute stress or infection. Your doctor will use these results alongside other tests and symptoms to guide diagnosis and treatment.
Short name
Eosinophil level
Frequently asked questions
What causes eosinophil levels to be higher than usual?
How long does it take to get results from this test?
Can diet or supplements affect eosinophil test results?
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