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Eosinophil count (absolute)

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

This test measures the number of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight infections and respond to allergic reactions.

Quick summary

["Eosinophil counts help diagnose and monitor conditions like allergies, asthma, or certain infections."]

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

Key facts at a glance

LOINC
11758-0
Short code
EFW from AC.Warsof77
Synonyms
EFW from AC.Warsof77
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
us-estimated-from-ac-warsof
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 Is Done

Your doctor may order this test to check for conditions affecting your immune system, such as allergies, asthma, parasitic infections, or certain blood disorders. It can also help evaluate symptoms like persistent itching, skin rashes, or unexplained fatigue.

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 usually takes a few minutes, and you may feel a brief pinch. If you’re nervous, let your healthcare provider know so they can help.

What the Test Results Mean

Elevated eosinophil counts may indicate allergies, asthma, parasitic infections, or inflammatory conditions. Lower-than-normal counts might suggest immune deficiencies or certain blood disorders. Your doctor will interpret results in the context of your symptoms and medical history.

Common Conditions Monitored

This test is often used to monitor conditions like chronic eosinophilic leukemia, eosinophilic esophagitis, or allergic reactions that don’t respond to standard treatments.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil count

Frequently asked questions

What causes eosinophil counts to rise?
Elevated eosinophil counts can result from allergies, asthma, parasitic infections, inflammatory diseases (like eosinophilic granulomatosis with polyangiitis), or certain medications. Chronic stress or emotional factors may also play a role in some cases.
How long does it take to get test results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will contact you once they’re ready to discuss the findings.
Can diet or supplements affect eosinophil counts?
While diet alone won’t directly change eosinophil counts, certain foods (like nuts, shellfish, or dairy) may trigger allergic reactions that indirectly influence test results. Avoiding known allergens before testing can help ensure accurate results.
  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