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Eosinophil Count (Peripheral Blood)

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 allergies and inflammation.

Quick summary

["Eosinophils help your body defend against parasites and allergic reactions."]

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

Key facts at a glance

LOINC
30381-8
Short code
Eosinophil NFr Spt
Synonyms
Eosinophil NFr Spt
Category
chemistry
Sample
sputum
Container
Sterile sputum container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
Specimen volume
3-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
TAT
4–24 hours
Order
routine

Why Is This Test Done?

Your doctor may order this test to diagnose or monitor conditions like allergies, asthma, parasitic infections, certain cancers (e.g., leukemia), or inflammatory diseases. It can also help assess how well treatments are working.

What to Expect Before the Test

You won’t need special preparation. A simple blood draw is all that’s required. The test is quick and usually done in a lab setting.

What the Results Mean

Elevated eosinophil counts may indicate allergic reactions, infections, or inflammatory conditions. Lower-than-normal counts could suggest immune system issues or certain blood disorders. Your doctor will interpret results in the context of your symptoms and medical history.

Common Conditions Linked to Eosinophil Levels

High eosinophil counts are often seen in allergies, asthma, parasitic infections, or autoimmune diseases like rheumatoid arthritis. Low levels may be linked to immune deficiencies or rare blood disorders.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: sputum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil Test

Frequently asked questions

How long does it take to get my eosinophil test results?
Results are typically available within 1–3 business days, depending on your lab’s processing time. Your doctor will discuss them with you during your follow-up visit.
Can food or medications affect my eosinophil test?
No specific diet or medications are required, but certain drugs (e.g., steroids) or infections may temporarily influence white blood cell counts. Your doctor will consider these factors when reviewing your results.
What if my eosinophil count is outside the normal range?
If your results are abnormal, your doctor may recommend additional tests (e.g., allergy testing, imaging) or adjust treatments to address the underlying cause.
  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