Eosinophil count in serum/plasma (absolute)
This test measures the number of eosinophils, a type of white blood cell, in your blood serum or plasma. Eosinophils help fight certain infections and respond to allergies and inflammation.
["Eosinophil levels can help diagnose or monitor conditions like allergies, asthma, parasitic infections, or certain cancers."]
Key facts at a glance
- LOINC
- 110145-0
- Short code
- ENA SM IgG Msmt Ser
- Synonyms
- ENA SM IgG Msmt Ser
- 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 You Need This Test?
Your healthcare provider may order this test if you have symptoms like persistent itching, skin rashes, unexplained weight loss, or if you’ve been diagnosed with conditions like asthma, eosinophilic esophagitis, or certain blood disorders. It can also help track treatment responses.
What to Expect Before the Test
No special preparation is needed. You’ll provide a blood sample, usually drawn from your arm. If you’re on blood thinners, let your provider know before the test.
What the Results Mean
Results are typically reported as the absolute number of eosinophils per microliter (µL) of blood. High levels may indicate allergies, infections, or autoimmune conditions, while low levels might suggest immune suppression or other health issues.
Common Conditions Monitored
Eosinophil counts are often checked in patients with allergic reactions, chronic lung diseases (like asthma), parasitic infections, or conditions like eosinophilic granulomatosis with polyangiitis (EGPA).
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Eosinophils play a key role in immune responses, particularly against parasites and allergens. Elevated counts may signal chronic inflammation or allergic reactions, while persistently low levels could indicate immune dysfunction or certain blood disorders.
Short name
Serum Eosinophil Count
Frequently asked questions
What causes eosinophil levels to rise?
How long does it take to get results?
Can diet or medications affect eosinophil counts?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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