Eosinophil count (qualitative or semi-quantitative blood smear evaluation)
This test checks the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to allergies or inflammation.
["Eosinophil levels can signal allergic reactions, infections, or other immune responses—your doctor may use this test to diagnose or monitor conditions like asthma, allergies, or parasitic infections."]
Key facts at a glance
- LOINC
- 40539-9
- Short code
- Eosinophil NFr DiafP Manual
- Synonyms
- Eosinophil NFr DiafP Manual
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 0
- Ref high
- 10
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- CPT
- 82105
- SNOMED
- 394971007
- 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 if you have symptoms like persistent itching, skin rashes, wheezing, or unexplained fatigue. It can also help diagnose conditions such as allergic reactions, parasitic infections, or certain blood disorders.
What to Expect Before the Test
No special preparation is needed. A simple blood draw from a vein in your arm is all that’s required. The test is usually done in a lab setting and may take a few minutes.
What the Results Mean
Results are qualitative (qualitative) or semi-quantitative, meaning they describe the presence or relative level of eosinophils rather than a precise number. High levels may indicate allergies, infections, or autoimmune conditions.
Common Conditions Monitored
Elevated eosinophils are often seen in allergic disorders (e.g., asthma, eczema), parasitic infections, or inflammatory conditions. Low levels may suggest immune suppression or other underlying issues.
Reference range
Normal: <10 ng/mLN/A
No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Eosinophils in Health and Disease
Short name
Eosinophil blood test (qualitative)
Frequently asked questions
What causes my eosinophil levels to be high?
Can diet or supplements affect eosinophil counts?
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