Biomarker: W207-IgE Lupin

Overview

W207-IgE Lupin measures lupin-specific immunoglobulin E (IgE) antibodies in blood, indicating immune sensitization to lupin proteins. IgE is involved in immediate hypersensitivity reactions, including food allergy. A high result may indicate sensitization to lupin, but it does not by itself confirm clinical allergy or predict reaction severity. A low or undetectable result reduces evidence of sensitization but does not completely exclude allergy; interpretation requires the clinical history and, when appropriate, supervised oral food challenge.

Clinical Use Cases

Support evaluation of suspected immediate hypersensitivity reactions after eating lupin or foods containing lupin flour.
Assess lupin sensitization in people with suspected or known peanut allergy, because cross-sensitization and clinical cross-reactivity may occur.
Provide an alternative to skin-prick testing when skin testing is unsuitable, unavailable, or affected by medications or skin conditions.
Support research into lupin allergy, IgE sensitization, and cross-reactivity with other legumes.
Help determine whether a medically supervised oral food challenge should be considered when the history and sensitization tests are inconclusive.

Specimen Types

Serum from venous blood.
Plasma may be accepted by some laboratory methods, but specimen requirements vary by assay.

Measurement Methods

Allergen-specific IgE immunoassay using a standardized lupin extract.
Automated fluorescence enzyme immunoassay or related solid-phase immunoassay.
Research methods may include ELISA, inhibition ELISA, immunoblotting, and immunoblot inhibition to characterize IgE binding and cross-reactive proteins.
Results are commonly reported as allergen-specific IgE concentration in kUA/L or equivalent units, with assay-specific classes or interpretive categories.

Test Preparation and Influencing Factors

Fasting is generally not required for an allergy blood test.
Patients should report all medications and supplements. Antihistamines generally do not affect blood specific-IgE measurements, although they may affect skin-prick testing; medications should not be stopped unless directed by a healthcare professional.
Total IgE concentration, age, atopic disease, and the assay used can influence interpretation.
A positive result indicates sensitization, not necessarily clinical allergy. Studies of lupin-sensitized patients have found that sensitization and clinical reactivity do not always correspond.
Lupin-specific IgE levels do not reliably predict the severity of a future reaction.
Cross-reactivity with peanut and other legumes can contribute to a positive result without proving that lupin caused a prior reaction.
Results should be interpreted with the exposure history, symptoms, and other testing. A medically supervised oral food challenge may be required to confirm or exclude lupin allergy when the diagnosis remains uncertain.