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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 caused by parasites and play a role in allergic reactions.

Quick summary

["Eosinophils help your body defend against certain infections and allergies, and this test helps doctors monitor their levels for health or condition-related reasons."]

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

Key facts at a glance

LOINC
31825-3
Short code
E coli K1 Ag Spec Ql
Synonyms
E coli K1 Ag Spec Ql
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 doctor may recommend this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergic reactions. It could also be used to check for conditions like parasitic infections, certain cancers, or inflammatory diseases.

What to Expect Before the Test

No special preparation is needed for this blood test. You may fast for 8–12 hours before the draw if instructed by your doctor, but this is not always required for a simple blood count.

How the Test Works

A small sample of your blood is taken from a vein, usually in your arm. The sample is then analyzed to count the number of eosinophils among your white blood cells.

What the Results Mean

High eosinophil counts may suggest allergies, parasitic infections, or certain autoimmune conditions. Low counts might indicate infections, stress, or other underlying health issues. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil blood count

Frequently asked questions

What does an elevated eosinophil count indicate?
Elevated eosinophils can signal conditions like asthma, allergic reactions, parasitic infections, or certain types of cancer (e.g., Hodgkin lymphoma). They may also appear in inflammatory or autoimmune disorders.
What could cause a low eosinophil count?
Low eosinophil counts can result from infections (like viral or bacterial), stress, certain medications, or conditions that suppress white blood cell production.
How often should I get this test?
Your doctor will determine how often to repeat this test based on your symptoms, diagnosis, or treatment plan. Follow-up may be needed if you have ongoing health concerns or are being monitored for a specific condition.
  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