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Eosinophil count in whole blood (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 caused by parasites and play a role in allergic reactions.

Quick summary

["Eosinophils help your body defend against certain infections and allergies, and this test helps doctors monitor their levels for health or condition-related reasons."]

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

Key facts at a glance

LOINC
27090-0
Short code
E histolyt IgA Sal Ql
Synonyms
E histolyt IgA Sal 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 This Test Might Be Ordered

Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It could also be used to check for conditions like parasitic infections, certain cancers, or autoimmune disorders that affect eosinophil levels.

What to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your vein (usually in your arm), and a small amount of blood will be drawn. This is quick and typically painless.

What the Test Results Mean

Elevated eosinophil counts may suggest allergies, parasitic infections, asthma, or certain types of cancer. Lower-than-normal levels might indicate immune system issues or other health concerns. Your results will be interpreted by your healthcare provider in the context of your overall health and symptoms.

Common Conditions Monitored

Eosinophil counts are often checked in patients with suspected allergic reactions, chronic lung diseases (like asthma), parasitic infections, or conditions such as eosinophilic esophagitis or certain blood cancers.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Eosinophil CBC

Frequently asked questions

How long does it take to get my test results back?
Results are usually available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the results with you during your follow-up visit.
Can I eat or drink before this test?
No special diet is required. You can eat and drink normally before your blood draw, as this test only involves a small blood sample.
What if my eosinophil count is out of the expected range?
If your results are abnormal, your healthcare provider will review them with you to determine the cause and next steps. This could involve further testing, treatment adjustments, or monitoring depending on your symptoms and medical history.
  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