Eosinophil count (qualitative manual differential blood smear)
This test checks the number of eosinophils—a type of white blood cell—in your blood using a manual microscopic examination. Eosinophils help fight certain infections and allergic reactions.
["Eosinophil counts help diagnose or monitor conditions affecting immune response or allergies."]
Key facts at a glance
- LOINC
- 68401-9
- Short code
- Eosinophil # Snv Manual
- Synonyms
- Eosinophil # Snv Manual
- Category
- chemistry
- Sample
- fluid
- Container
- Sterile tube
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- manual-count
- Specimen volume
- 2-5 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h
- Hemolysis max
- 300
- 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, allergies, and some chronic inflammatory conditions. They release chemicals that help control immune responses, including those triggered by allergens or infections.
Why Might This Test Be Ordered?
Your doctor may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergic reactions. It can also help evaluate conditions such as parasitic infections, certain cancers (like Hodgkin lymphoma), or autoimmune disorders.
How Is the Test Performed?
A small blood sample is drawn from your arm. The sample is then spread thinly on a microscope slide and examined under a high-powered microscope by a trained lab technician. The technician counts and identifies eosinophils among other white blood cells.
What Do Results Mean?
Results are reported as a qualitative assessment (high, normal, or low eosinophil count) rather than a specific numeric value. High eosinophil counts may indicate allergic reactions, parasitic infections, or certain inflammatory diseases. Low counts may suggest immune suppression or other underlying conditions.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Elevated eosinophils often signal allergic or parasitic conditions, asthma, or certain autoimmune diseases. Low eosinophils may occur with infections that suppress white blood cell production or chronic illnesses like HIV. This test is a key diagnostic tool for guiding treatment decisions.
Short name
Eosinophil count (qualitative)
Frequently asked questions
When could I expect to get results?
What does a high eosinophil count mean?
Can I eat or drink before 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