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Eosinophil count in blood (qualitative or semi-quantitative)

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

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

Quick summary

["Eosinophils help protect your body from harmful substances but can become too high in certain conditions."]

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

Key facts at a glance

LOINC
5151-6
Short code
E histolyt Ab Ser HA-aCnc
Synonyms
E histolyt Ab Ser HA-aCnc
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ha
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 This Test Might Be Ordered

Your doctor may recommend this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be used to monitor conditions like parasitic infections, certain cancers, or allergic reactions.

What to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your arm or hand to draw blood. The process usually takes a few minutes.

What the Test Results Mean

Results are qualitative (qual) or semi-quantitative, meaning they describe whether eosinophil levels are elevated or not. High levels may suggest allergies, infections, or other conditions requiring further evaluation.

Common Conditions Linked to Abnormal Results

High eosinophil counts may be linked to allergies, asthma, parasitic infections, certain cancers (like lymphoma or leukemia), or inflammatory conditions. Low levels might indicate immune suppression or other underlying health issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated eosinophils can indicate chronic inflammation, allergic reactions, or parasitic infections. Doctors may use these results alongside other tests to diagnose or guide treatment for conditions like asthma, eosinophilic esophagitis, or certain autoimmune disorders.

Short name

Eosinophil test

Frequently asked questions

What causes eosinophils to be high?
Eosinophils can rise due to allergies, asthma, parasitic infections, certain cancers, or inflammatory diseases. Stress, medications, or other immune responses may also play a role.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on your lab’s processing time.
Can I eat or drink before this test?
No special diet or fasting is required for this blood test. However, always follow your doctor’s instructions for any specific preparations.
  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