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Eosinophil Count (Qualitative or Semi-Quantitative Blood Evaluation)

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

This test checks the presence or level of eosinophils, a type of white blood cell involved in allergic reactions and fighting certain infections.

Quick summary

["Eosinophils help identify possible allergies, infections, or inflammatory conditions."]

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

Key facts at a glance

LOINC
71603-5
Short code
Eosinophil NFr.DF Pcar Manual
Synonyms
Eosinophil NFr.DF Pcar Manual
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
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 Is an Eosinophil?

Eosinophils are a type of white blood cell that plays a role in defending the body against parasites, allergens, and some infections. They release chemicals to combat these threats. When levels are abnormal, it may signal underlying health concerns.

Why Might You Need This Test?

Your healthcare provider may order this test to diagnose or monitor conditions such as allergies, asthma, parasitic infections, or certain autoimmune diseases. It can also help assess reactions to medications or treatments.

How Is the Test Performed?

A blood sample is taken from a vein, usually in your arm. The sample is then examined under a microscope to count or identify eosinophils. The test may be qualitative (just presence/absence) or semi-quantitative (approximate levels).

What Are Common Results?

Results are typically reported as qualitative (positive/negative) or semi-quantitative (e.g., low, normal, or elevated levels). Elevated eosinophil counts may indicate allergic reactions, infections, or inflammatory conditions. Low levels may suggest immune suppression or other health issues.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil Test (Qualitative)

Frequently asked questions

Why do eosinophils rise or fall in my blood?
Elevated eosinophils often point to allergies, parasitic infections, asthma, or certain autoimmune diseases. Low levels may suggest conditions like HIV, certain cancers, or immune deficiencies. Always discuss results with your doctor for proper interpretation.
How long does it take to get results?
Results are usually available within 1–2 business days, depending on lab processing times. Your healthcare provider will contact you once they are ready.
Can I eat or drink anything before this test?
No special preparation is needed for this test. However, avoid heavy meals or alcohol before the blood draw to ensure accurate results.
  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