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Eosinophil count in plasma (qualitative)

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

This test checks the presence of eosinophils, a type of white blood cell, in your plasma. Eosinophils help fight certain infections and respond to allergies or inflammatory conditions.

Quick summary

["Eosinophils may rise in allergic reactions, infections, or inflammatory diseases—your doctor will interpret results in context with your symptoms and other tests."]

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

Key facts at a glance

LOINC
73961-5
Short code
Ecoli+Kpneu+Paeru rRNA Bld Pos FISH
Synonyms
Ecoli+Kpneu+Paeru rRNA Bld Pos FISH
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
fish
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like persistent itching, skin rashes, asthma, or unexplained allergies. It can also help diagnose conditions like parasitic infections, certain cancers, or autoimmune disorders.

What to Expect Before the Test

No special preparation is needed. You’ll provide a blood sample drawn from your vein, and the plasma will be tested for eosinophil presence. Results are qualitative (yes/no) rather than a numeric count.

What the Results Mean

A positive result indicates elevated eosinophils, which may signal an allergic reaction, infection, or inflammatory process. A negative result means no detectable eosinophils in the sample.

Common Conditions Linked to Eosinophil Levels

High eosinophil counts can be associated with allergies, asthma, parasitic infections, certain cancers (like lymphoma), or autoimmune diseases. Low or absent levels are less commonly evaluated in this test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Eosinophil screening is often used as a preliminary test to narrow down potential causes of symptoms like chronic itching, unexplained skin rashes, or respiratory issues. While not a definitive diagnostic tool, it can guide further testing (e.g., allergy testing, stool samples for parasites).

Short name

Eosinophil Screen (Plasma)

Frequently asked questions

How often will I need this test?
This is typically a one-time screening test unless your symptoms persist or your doctor suspects a recurring condition. Follow-up may include additional blood tests or consultations.
What if my results are positive?
A positive result may prompt further evaluation, such as allergy testing, blood parasite tests, or imaging studies. Your doctor will discuss next steps based on your overall health and symptoms.
Can I eat or drink before this test?
No restrictions apply. You can eat, drink water, and continue normal activities before the blood draw.
  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