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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 certain infections and respond to allergic reactions.

Quick summary

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

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

Key facts at a glance

LOINC
32593-6
Short code
Eosinophil NFr Spec
Synonyms
Eosinophil NFr Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 healthcare provider may recommend this test if you have symptoms like persistent itching, skin rashes, wheezing, or unexplained fatigue. It could also be part of an evaluation for conditions like asthma, allergies, or certain infections.

What to Expect Before the Test

No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw a blood sample. The process is quick and usually painless.

What the Results Mean

Higher-than-normal eosinophil counts may suggest allergies, asthma, parasitic infections, or other inflammatory conditions. Lower-than-normal counts might indicate immune suppression or certain blood disorders.

Common Conditions Linked to Eosinophil Counts

Elevated eosinophils are often linked to allergic reactions, asthma, parasitic infections, or certain autoimmune diseases. Low eosinophil counts may be associated with conditions like HIV, certain cancers, or immune deficiencies.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil Blood Test

Frequently asked questions

What does an abnormal eosinophil count mean?
An abnormal count (either high or low) doesn’t always indicate a specific condition on its own. It often helps guide further testing or treatment plans, depending on your symptoms and overall health.
How often should I get this test?
Your doctor will determine how often you need this test based on your medical history, symptoms, and treatment plan. Follow-up may be needed if you’re being treated for conditions like allergies or infections.
Can diet or medications affect eosinophil counts?
Certain medications (like steroids) or chronic conditions (like asthma) can influence eosinophil levels. Your doctor may ask you to avoid certain supplements or medications before the test if needed.
  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