Skip to content

Eosinophil count (serum/plasma mass concentration)

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, allergens, and certain bacteria.

Quick summary

["Eosinophils can rise in response to infections, allergies, or inflammatory conditions."]

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

Key facts at a glance

LOINC
7395-7
Short code
Helminthosporium IgE Qn
Synonyms
Helminthosporium IgE Qn
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

When Eosinophils Are High

Elevated eosinophil counts may indicate conditions such as allergic reactions, parasitic infections, asthma, or certain autoimmune diseases. They can also appear in chronic conditions like certain types of lung disease or inflammatory bowel disease.

When Eosinophils Are Low

Low eosinophil counts might suggest immune system suppression, certain infections (like viral or fungal), or conditions affecting bone marrow production of white blood cells.

What Causes Changes in Eosinophil Levels?

Eosinophil levels can fluctuate due to infections (especially parasitic or fungal), allergic reactions, medications (like steroids), or underlying health conditions affecting your immune system.

How Is This Test Performed?

A blood sample is drawn, and your white blood cells are analyzed under a microscope or through automated testing to count eosinophils. The result is expressed as a count per microliter of blood.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated eosinophils may signal conditions requiring further investigation, such as allergies, infections, or inflammatory diseases. Low levels could indicate immune dysfunction or other health concerns that need medical evaluation.

Short name

Eosinophil Level

Frequently asked questions

Why might my doctor order this test?
Your doctor may order this test to diagnose or monitor conditions like allergies, parasitic infections, asthma, or other immune-related disorders. It can also help assess response to treatment.
What do my results mean?
Results are compared to standard ranges for your age and health. If your levels are outside the normal range, your doctor will discuss potential causes and next steps with you.
Can I affect my eosinophil levels?
Yes, factors like infections, allergies, stress, or certain medications can temporarily change eosinophil counts. Lifestyle changes or treatments may influence these levels over time.
  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