Eosinophil Count (Manual Differential Blood Count)
This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to allergies and inflammation.
["Eosinophil levels can help diagnose or monitor conditions like allergies, asthma, parasitic infections, or other immune-related disorders."]
Key facts at a glance
- LOINC
- 12209-3
- Short code
- Eosinophil NFr Fld Manual
- Synonyms
- Eosinophil NFr Fld Manual
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- CPT
- 86430
- 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 Is This Test Done?
Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, wheezing, or unexplained fatigue. It may also be used to check for conditions like parasitic infections, certain cancers, or reactions to medications.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm to draw blood. The process usually takes a few minutes. If you’re nervous, let your healthcare provider know.
What Happens During the Test?
Blood is collected in a tube and sent to the lab. A technician will manually count eosinophils under a microscope. This method provides detailed results for specific conditions.
What Do the Results Mean?
Results are reported as the number of eosinophils per microliter (µL) of blood. High levels may indicate allergies, infections, or inflammatory conditions, while low levels may suggest immune suppression or other health issues.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Eosinophils play a key role in defending against parasites, managing allergic reactions, and responding to chronic inflammation. Elevated counts can signal conditions like asthma, eosinophilic esophagitis, or certain cancers. Low counts may raise concerns about immune dysfunction or blood disorders.
Short name
Eosinophil Blood Test
Frequently asked questions
What causes eosinophil levels to be high?
What causes eosinophil levels to be low?
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