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Eosinophil count (qualitative, serum/plasma)

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 inflammatory conditions.

Quick summary

["Eosinophil levels 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
112154-0
Short code
Herring worm IgE Qn IA
Synonyms
Herring worm IgE Qn IA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia
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 parasitic infections, certain cancers, or autoimmune disorders.

What to Expect Before the Test

No special preparation is needed. A simple blood draw is performed, usually from a vein in your arm. The sample is then analyzed to count eosinophils.

What the Results Mean

Results are qualitative (qualitative rather than quantitative), meaning they indicate whether eosinophil levels are elevated or normal rather than providing exact numbers. High levels may suggest allergies, infections, or other conditions affecting eosinophils.

Common Conditions Linked to Eosinophil Levels

Elevated eosinophils are often seen in allergic reactions, parasitic infections, certain lung diseases (like asthma or eosinophilic granulomatosis with polyangiitis), or conditions like hypereosinophilic syndrome.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated eosinophils can help diagnose or guide treatment for conditions like allergic disorders, parasitic infections, or inflammatory diseases. Low or normal levels may indicate no immediate concern but could still warrant further investigation if symptoms persist.

Short name

Eosinophil screening

Frequently asked questions

What causes eosinophils to rise?
Eosinophils can increase due to allergies, parasitic infections, asthma, certain cancers (like lymphoma), or autoimmune diseases. Stress, certain medications, or chronic conditions like inflammatory bowel disease may also play a role.
What should I do if my eosinophil count is high?
If your test shows elevated eosinophils, your doctor may recommend further testing (like allergy testing, parasite screenings, or imaging) to identify the cause. Follow-up may include treatment adjustments if allergies or infections are suspected.
Can diet or lifestyle changes affect eosinophil levels?
Dietary changes alone won’t directly alter eosinophil counts, but managing allergies (e.g., avoiding triggers) or treating infections can help reduce elevated levels. Lifestyle factors like stress management may indirectly support immune balance.
  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