Eosinophil count (qualitative or semi-quantitative blood differential analysis)
This test measures the number of eosinophils, a type of white blood cell involved in allergic reactions and fighting certain infections.
["Eosinophils help identify allergies, infections, or inflammatory conditions."]
Key facts at a glance
- LOINC
- 50340-9
- Short code
- Eosinophil Nose Ql Hansel Stn
- Synonyms
- Eosinophil Nose Ql Hansel Stn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 1.5
- Ref high
- 9
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- hansel-stain
- CPT
- 83002
- 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 Is an Eosinophil?
Eosinophils are a type of white blood cell that play a role in defending the body against parasites, allergens, and some infections. They release chemicals to combat these threats and can become elevated in response to certain conditions.
Why Might You Need This Test?
Your doctor may order this test to check for conditions like allergies, asthma, parasitic infections, or certain autoimmune diseases where eosinophil levels might be unusually high or low.
How Is the Test Performed?
A blood sample is drawn from a vein, typically in your arm. The sample is then examined under a microscope to count eosinophils as part of a complete blood count (CBC) or a specific differential test.
What Do Results Mean?
Results are qualitative (yes/no) or semi-quantitative (approximate range), indicating whether eosinophil levels are elevated, normal, or low. Elevated levels may suggest allergies, asthma, infections, or other inflammatory conditions.
Reference range
Follicular: 1.5-9.0 mIU/mLN/A
For females: inform if menstrual cycle status. For certain tests, timing within menstrual cycle may matter.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated eosinophils can signal allergic reactions, parasitic infections, certain lung diseases (like asthma or eosinophilic granulomatosis with polyangiitis), or other inflammatory or autoimmune conditions. Low levels may indicate stress, certain infections, or other underlying health issues. This test helps guide treatment decisions.
Short name
Eosinophil test
Frequently asked questions
What causes eosinophil levels to be high?
How long does it take to get results?
Can I do anything to prepare for 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