Allergen Profile, Egg White, IgE With Component Reflexes

Casandra

Casandra Test Code LC74765Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 603940CPT Code 86003

Allergen Profile, Egg White, IgE With Component Reflexes

Clinical Use

Use

The measurement of specific immunoglobulin E (IgE) to individual components of an allergen, either purified native or recombinant, is referred to as component resolved diagnosis (CRD).1-4 This approach represents an improvement over traditional measurement of IgE to allergen extracts that contain a mixture of proteins. The pattern of specific IgE reactivity to component allergens can predict which patients are at higher risk for systemic allergic reactions versus those who are sensitized but clinically tolerant. CDR can also be used to predict which patients are at risk for more severe reactions and which patients are likely to have milder symptoms.

Special Instructions

If the initial analysis of egg white IgE is ≥0.35 kU/L, reflex testing with ovalbumin IgE and ovomucoid IgE will be conducted. The test includes allergens such as egg white and components like Gal d 1 (ovomucoid) and Gal d 2 (ovalbumin). Quantifying IgE levels aids in determining when to conduct oral food challenge tests, aiming to reduce the risk of serious reactions.

Limitations

Allergen-specific IgE assays do not provide absolute positive and negative predictive values for allergic diseases. Diagnostic determinations must include clinical history. While component resolved IgE testing improves evaluation over whole extracts, it cannot replace clinical histories and oral food challenges in most cases. Sensitization to unidentified determinants not in extracts or components may cause symptoms in rare instances.

Test Details