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Eosinophil count (qualitative, blood smear evaluation)

Published: August 9, 2026Updated: August 16, 2026

This test checks the presence and number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight certain infections and respond to allergies.

Quick summary

["Eosinophil counts help diagnose or monitor conditions linked to elevated white blood cells."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
29905-7
Short code
E histolyt Ag Stl Ql IA
Synonyms
E histolyt Ag Stl Ql IA
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be used to evaluate conditions like parasitic infections, certain cancers, or autoimmune disorders.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm to draw blood. The process takes a few minutes, and you may feel a brief pinch. If you’re on blood thinners, let your provider know before the test.

What the Results Mean

Results are qualitative (yes/no) rather than numerical. High levels of eosinophils may suggest allergies, infections, or inflammatory conditions. Low levels might indicate immune suppression or other health concerns.

Common Conditions Monitored

This test helps track conditions like allergic reactions, parasitic infections, eosinophilic esophagitis, or certain blood disorders. It’s also used in research or specialized diagnostic settings.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil count (qualitative)

Frequently asked questions

What causes elevated eosinophils in my blood?
Elevated eosinophils can result from allergies, parasitic infections, asthma, certain cancers (like leukemia), or inflammatory diseases. Chronic conditions or medications may also play a role. Your provider will consider your symptoms and medical history.
How long will I need to wait for results?
Results are typically available within 1–3 business days, depending on lab processing times. Follow-up with your provider to discuss findings.
Can I eat or drink before this test?
No dietary restrictions apply. You can eat, drink water, and take medications as usual unless instructed otherwise.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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