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Eosinophil count (serum-derived absolute cell count)

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 certain infections and respond to allergies and inflammation.

Quick summary

["Eosinophil counts help diagnose and monitor conditions affecting immune response and allergic reactions."]

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

Key facts at a glance

LOINC
21518-6
Short code
ENA Scl70 IgG Ser Ql
Synonyms
ENA Scl70 IgG Ser Ql
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
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 Might This Test Be Ordered?

Your healthcare provider may order this test to investigate symptoms like persistent itching, skin rashes, asthma, or chronic sinus issues. It can also help diagnose conditions such as allergies, parasitic infections, or certain autoimmune diseases.

What to Expect Before the Test

No special preparation is needed. A blood sample is drawn from a vein, usually in your arm. The process is quick and typically painless.

What the Results Mean

Elevated eosinophil counts may indicate allergic reactions, infections (like parasites), or inflammatory conditions. Lower-than-normal counts might suggest immune suppression or certain blood disorders.

Common Conditions Monitored

This test is often used to monitor conditions like asthma, eosinophilic esophagitis, certain cancers (e.g., Hodgkin lymphoma), and chronic inflammatory diseases.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Eosinophil count

Frequently asked questions

What causes eosinophils to be high?
High eosinophil counts can result from allergies, asthma, parasitic infections, certain cancers, or inflammatory conditions. Chronic stress or certain medications may also play a role.
How long does it take to get results?
Results are usually available within 24 to 48 hours, depending on your lab’s processing schedule.
Can diet affect eosinophil levels?
Diet alone typically does not significantly alter eosinophil counts, but certain foods or supplements (e.g., fish oil, probiotics) may influence inflammation indirectly. Always follow your provider’s advice.
  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