Biomarker: F075-IgE Egg (Yolk)

Overview

F075-IgE Egg (Yolk) measures serum immunoglobulin E (IgE) antibodies that bind to egg-yolk allergens. Egg-yolk allergens include alpha-livetin, also known as chicken serum albumin or Gal d 5, and yolk glycoprotein 42, also known as Gal d 6. A detectable result indicates sensitization to egg-yolk proteins, but does not by itself confirm a clinically relevant egg allergy or predict reaction severity. The test is clinically useful when interpreted with symptoms, exposure history, and other allergy tests, particularly when evaluating suspected egg allergy or bird-egg syndrome.

Clinical Use Cases

Supporting evaluation of suspected IgE-mediated egg allergy when symptoms occur after eating egg or egg-containing foods.
Assessing sensitization specifically to egg yolk, in conjunction with whole-egg and egg-white testing.
Supporting evaluation of bird-egg syndrome, in which sensitization to avian allergens may cross-react with Gal d 5 in egg yolk.
Helping characterize egg-allergen sensitization in allergy research and component-resolved diagnostic evaluations.
Supporting, but not replacing, a medically supervised oral food challenge when the diagnosis remains uncertain. Oral food challenge is the reference method for confirming food allergy.

Specimen Types

Venous blood, typically collected as serum.
Plasma may be accepted by some validated immunoassay platforms, according to the performing laboratory’s requirements.

Measurement Methods

Fluorescent enzyme immunoassay.
Enzyme-linked immunosorbent assay.
Chemiluminescent immunoassay.
Immunoblot or multiplex component-resolved immunoassay in selected research or specialist settings.
Results are commonly reported quantitatively in ( \mathrm{kUA/L} ), although units and analytical reference ranges vary by assay.

Test Preparation and Influencing Factors

Fasting is generally not required for an allergy blood test.
Tell the healthcare professional about all medications and supplements. Do not stop prescribed or over-the-counter medicines unless specifically instructed.
Antihistamines usually do not interfere with serum-specific IgE testing, unlike skin-prick testing, but medication instructions should follow the ordering clinician or laboratory.
Results should be interpreted with the timing, amount, and form of egg consumed and the patient’s reported symptoms.
Egg-yolk allergenicity may be affected by heating. Gal d 5 is partially heat-labile, so results for egg yolk do not necessarily predict reactions to every preparation of egg.
A positive result indicates sensitization and does not independently establish food allergy, clinical reactivity, or reaction severity.
Total IgE levels, atopic dermatitis, age, assay characteristics, and cross-sensitization to avian allergens may influence interpretation.
Reference ranges, detection limits, and reporting classes differ among assays; results should be interpreted using the reporting laboratory’s criteria.