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Total IgE Antibody Concentration (Serum)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of Immunoglobulin E (IgE) in your blood, a type of antibody linked to allergic reactions.

Quick summary

["IgE levels help identify allergies or immune responses."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
13834-7
Short code
Total IgE SmQn RAST
Synonyms
Total IgE SmQn RAST
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
10
Ref high
40
Critical range
— – 500 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rast
CPT
84484
SNOMED
302774002
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

What Is Immunoglobulin E (IgE)?

IgE is a protein produced by your immune system in response to allergens like pollen, dust, or certain foods. While small amounts are normal, higher levels may signal allergies or other immune conditions.

Why Might You Need This Test?

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

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The sample is sent to a lab where it is analyzed using an immunoassay method to detect and measure IgE levels.

What Do Results Mean?

Results are compared to reference ranges, which vary by lab. Elevated IgE levels may indicate allergies or immune-related conditions, while normal or low levels may suggest no active allergic response.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Total Immunoglobulin E (IgE) Level

Frequently asked questions

What causes elevated IgE levels?
Common causes include allergies to foods, pollen, dust mites, or pets. Other conditions like asthma, eczema, or certain parasitic infections may also be linked to elevated IgE.
What causes low IgE levels?
Low IgE levels are less common but may occur in people with certain immune deficiencies or those who have had severe allergic reactions in the past (e.g., anaphylaxis). Rarely, they may also be seen in some genetic conditions.
How often should I get this test?
Your doctor will determine the frequency based on your symptoms, medical history, or treatment needs. Follow-up tests may be scheduled if your IgE levels change or if symptoms persist.
  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 17, 2026. · Read our editorial policy