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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

["Eosinophils can signal allergic reactions, infections, or certain medical conditions."]

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

Key facts at a glance

LOINC
20813-2
Short code
E coli F41 Islt Ql Aggl
Synonyms
E coli F41 Islt Ql Aggl
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
aggl
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 Is Done

Your doctor may order an eosinophil count to check for conditions like allergies, asthma, parasitic infections, or certain autoimmune diseases. It may also be used to monitor treatment progress or diagnose unexplained symptoms such as itching, skin rashes, or persistent coughing.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood, which usually takes a few minutes. If you’re nervous, let your healthcare provider know—they can help make the process more comfortable.

What the Results Mean

Eosinophil counts can vary based on health, age, and activity level. High levels may indicate allergies, infections, or inflammatory conditions, while very low levels might suggest immune system issues or certain medications. Your doctor will interpret results in the context of your overall health.

Common Conditions Linked to Eosinophil Levels

Elevated eosinophils are often seen in conditions like allergic reactions, asthma, parasitic infections, or certain cancers (e.g., Hodgkin lymphoma). Low eosinophil counts may be linked to immune deficiencies or medications that suppress white blood cells.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil Level

Frequently asked questions

How long will I need to wait for my results?
Results are typically available within 1–3 business days, depending on your lab. If you have urgent concerns, ask your doctor about follow-up timing.
Can I eat or drink before this test?
You can eat and drink normally before this test, as it doesn’t require fasting. However, inform your doctor if you’re on blood-thinning medications or have a history of bleeding disorders.
Does this test hurt?
Most people experience only mild discomfort or a slight pinch when blood is drawn. The area may feel sore for a few minutes afterward, but it’s usually temporary.
  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