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Eosinophil count (serum/plasma mass concentration)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of eosinophils, a type of white blood cell, in your blood. Eosinophils help fight infections and respond to allergies or inflammation.

Quick summary

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

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

Key facts at a glance

LOINC
31382-5
Short code
E coli VTN2 Ab Stl-aCnc
Synonyms
E coli VTN2 Ab Stl-aCnc
Category
chemistry
Sample
stool
Container
Clean container
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 g
Stability
Refrigerated: 24h, Frozen: 7d
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may order this test to check for conditions affecting your immune system, such as allergies, asthma, parasitic infections, or certain blood disorders. It could also be part of a broader evaluation for unexplained symptoms like persistent itching, skin rashes, or digestive issues.

What to Expect Before the Test

No special preparation is usually needed. You may have a small needle inserted into your arm or hand to draw blood. If you’re on blood thinners, let your doctor know before the test.

What the Results Mean

Elevated eosinophil levels may indicate allergies, infections, or inflammatory conditions. Lower-than-normal levels might suggest certain immune deficiencies or blood disorders. Your doctor will interpret results in the context of your overall health and symptoms.

Common Conditions Monitored

Eosinophil counts are often checked in patients with allergies, asthma, parasitic infections (like hookworm or giardiasis), or autoimmune diseases like rheumatoid arthritis.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil level

Frequently asked questions

What causes eosinophil levels to rise?
Elevated eosinophils can be caused by allergies, asthma, parasitic infections, certain cancers (like lymphoma), or inflammatory conditions. Stress or certain medications may also temporarily affect levels.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your doctor will discuss the findings with you during your follow-up visit.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor specifies otherwise. This test doesn’t require fasting, unlike some other blood tests.
  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