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Total Serum/Plasma 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 allergies and inflammation.

Quick summary

["Eosinophil counts help diagnose and monitor conditions affecting your immune system."]

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

Key facts at a glance

LOINC
39549-1
Short code
Escargot IgE/IgE total %
Synonyms
Escargot IgE/IgE total %
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

What Are Eosinophils?

Eosinophils are a type of white blood cell that play a role in defending the body against parasites, allergies, and certain infections. They release chemicals to combat these threats and can also contribute to inflammation in some conditions.

When Might This Test Be Ordered?

Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained fatigue. It could also be used to check for conditions like allergies, parasitic infections, or certain blood disorders.

Common Conditions Monitored

High eosinophil counts may suggest allergies, asthma, parasitic infections, or certain autoimmune diseases. Low counts might indicate infections, bone marrow disorders, or other immune system issues.

How Is the Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of eosinophils present in your blood.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil count

Frequently asked questions

Why do I need this test?
Your doctor may recommend this test to investigate symptoms like persistent itching, unexplained rashes, breathing difficulties, or other signs of an allergic reaction or immune-related condition.
What do my results mean?
Results are compared to a general reference range for healthy adults. High or low counts may signal potential health concerns, but your doctor will discuss these findings in the context of your overall health and symptoms.
Can I eat or drink before the test?
Typically, no special preparation is needed. However, follow any specific instructions your healthcare provider gives you, as they may vary depending on your medical history or other tests you’re having.
  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