Immunoglobulin E (IgE)

What is Immunoglobulin E?

Immunoglobulin E (IgE) is an antibody class that plays a central role in allergic reactions and parasitic infections. While present in very low concentrations in healthy individuals, IgE triggers immediate hypersensitivity reactions when it encounters specific allergens.

Why is it Tested?

Doctors order total IgE to evaluate allergic diseases like asthma, eczema, or food allergies, investigate suspected parasitic infections, or assess unexplained eosinophilia. It’s often ordered alongside specific IgE allergen testing to guide allergy management.

Normal Ranges

Reference ranges vary by age and lab:

Adults: <100 IU/L

IgE levels are typically higher in children and decrease with age. Values can be significantly elevated in allergic individuals or those with parasitic infections.

Reference ranges vary by authority. Track yours across multiple standards with automatic unit conversions in LabsVault.

What do Abnormal Results Mean?

Abnormal results are not a diagnosis. Always discuss your results with a qualified healthcare provider before making any medical decisions.

High IgE

Elevated levels may indicate:

Allergic diseases (asthma, atopic dermatitis, food allergies)
Parasitic infections
Aspergillosis or fungal infections
Immunodeficiency disorders
Certain cancers (lymphoma, myeloma)

Normal IgE

Normal levels suggest:

Absence of active allergic disease
No current parasitic infection
Possible non-IgE mediated allergies
Need for specific allergen testing if symptoms persist

How to Track Over Time

Total IgE fluctuates with allergen exposure, seasonal patterns, and treatment effectiveness. Tracking levels helps monitor allergy treatment response and detect new sensitizations. Values may remain elevated even between allergic episodes in sensitized individuals.

Immunoglobulin E