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Eosinophil count in blood (qualitative or semi-quantitative)

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

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

Quick summary

["Eosinophils can signal allergic reactions, infections, or other immune responses."]

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

Key facts at a glance

LOINC
7880-8
Short code
E histolyt Ab Ser-aCnc
Synonyms
E histolyt Ab Ser-aCnc
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 allergies. It could also be used to monitor conditions like asthma, allergies, parasitic infections, or certain autoimmune diseases.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for a few hours before the blood draw, but this is rare for this type of test. Bring any medications you’re currently taking to your appointment.

How the Test Works

A small amount of blood is drawn from a vein, typically in your arm. The sample is then examined under a microscope to count eosinophils. The result may be qualitative (yes/no presence) or semi-quantitative (approximate count).

What the Results Mean

High eosinophil counts may indicate allergies, asthma, parasitic infections, or other inflammatory conditions. Low counts might suggest certain infections (like viral) or immune disorders. Your doctor will interpret results in the context of your symptoms and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Eosinophil counts are important for diagnosing and managing conditions like allergic reactions, parasitic infections, eosinophilic esophagitis, and certain lung diseases. They can also help track response to treatment for these conditions.

Short name

Eosinophil blood test

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times.
What does an elevated eosinophil count mean?
An elevated count often suggests an allergic reaction, asthma, parasitic infection, or another inflammatory condition. Your doctor will discuss possible causes and next steps with you.
Can I eat or drink before this test?
No special diet is required, but always follow your doctor’s instructions. If fasting is advised, avoid food or liquids except water for a specified time before the draw.
  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