Eosinophil Count (Qualitative Blood Differential)
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.
["Eosinophils help protect your body from harmful substances and infections."]
Key facts at a glance
- LOINC
- 71646-4
- Short code
- Eosinophil NFr.DF Fld Manual
- Synonyms
- Eosinophil NFr.DF 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
- 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 against parasites and managing allergic reactions. They also help reduce inflammation in some conditions. When present in higher-than-normal amounts, they may signal an underlying issue like allergies, asthma, or certain infections.
Why Might You Need This Test?
Your doctor may order this test to investigate symptoms such as persistent itching, skin rashes, asthma, or unexplained weight loss. It can also help diagnose conditions like eosinophilic esophagitis, certain infections, or autoimmune disorders.
How Is This 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 full blood count (CBC). This is a quick and painless procedure.
What Do Results Mean?
Results are reported as qualitative (not numerically quantified) and indicate whether eosinophil levels are elevated, normal, or low relative to other white blood cells. High eosinophil counts may suggest allergic reactions, infections, or inflammatory conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Elevated eosinophils can indicate conditions like allergic disorders, parasitic infections, certain cancers (e.g., leukemia), or autoimmune diseases. Low levels may suggest immune suppression or other health concerns.
Short name
Eosinophil count (qualitative)
Frequently asked questions
What causes eosinophils 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