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Immunoglobulin E (IgE) in Serum or Plasma by Immunoassay

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

This test measures the amount of Immunoglobulin E (IgE), a type of antibody in your blood. IgE is involved in allergic reactions and responses to parasites.

Quick summary

["IgE helps identify allergies or immune system responses."]

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

Key facts at a glance

LOINC
42513-2
Short code
IgE CSF-aCnc
Synonyms
IgE CSF-aCnc
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What Does IgE Measure?

IgE is part of your immune system’s response to allergens (substances like pollen, dust, or certain foods) and parasites. High levels may indicate allergies, asthma, or other immune-related conditions.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms like sneezing, itching, hives, or breathing difficulties that suggest allergies. It can also help diagnose conditions like allergic rhinitis, asthma, or certain parasitic infections.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The blood is then sent to a lab where it is analyzed using an immunoassay method to detect IgE antibodies.

What Are Common Results?

Results are not always given in a single number, as they depend on symptoms and clinical context. High IgE levels may suggest allergies or immune responses, while low levels may indicate a reduced allergic reaction tendency.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgE Level

Frequently asked questions

Why might my IgE test be elevated?
Elevated IgE levels often point to allergies, asthma, or other allergic conditions. They can also be linked to parasitic infections or certain autoimmune disorders. Your doctor will consider your symptoms and medical history to interpret results.
What if my IgE test is normal?
A normal IgE level doesn’t rule out allergies or other conditions. Some people with allergies may have normal IgE levels, so further testing or allergy evaluations may still be needed.
How often should I get this test?
The frequency depends on your symptoms and medical needs. Your doctor may recommend retesting if symptoms change or if additional evaluation is required, such as allergy skin tests or other blood work.
  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