Biomarker: T010-IgE Walnut

Overview

T010-IgE Walnut measures serum immunoglobulin E (IgE) antibodies directed against walnut allergens, indicating sensitization to walnut. IgE is an antibody involved in immediate allergic reactions, including symptoms that may affect the skin, gastrointestinal tract, respiratory system, or cardiovascular system. A detectable or elevated result may support walnut sensitization, while a low or undetectable result reduces but does not eliminate the possibility of allergy. Walnut-specific IgE is clinically useful when interpreted with the patient’s history, examination, and, when necessary, a medically supervised oral food challenge; the blood result alone does not confirm allergy or predict reaction severity.

Clinical Use Cases

Evaluation of suspected IgE-mediated walnut allergy.
Assessment of patients with a history of symptoms after eating walnut.
Identification of walnut sensitization when skin-prick testing is unsuitable or cannot be performed.
Support for distinguishing walnut sensitization from clinically relevant allergy when combined with medical history and other testing.
Selection of patients who may require a supervised oral food challenge when the diagnosis remains uncertain.
Research assessment of walnut-specific IgE and component sensitization, including antibodies to Jug r 1 and Jug r 4.

Specimen Types

Venous blood serum.
Plasma may be accepted by some laboratory methods, according to the assay’s requirements.

Measurement Methods

In-vitro allergen-specific IgE immunoassay using a walnut extract.
Fluorescence enzyme immunoassay or other solid-phase immunoassays.
Component-resolved diagnostics measuring IgE to individual walnut allergens, such as Jug r 1, Jug r 3, and Jug r 4.
Results are commonly reported in kUA/L or an equivalent standardized allergen-specific IgE unit.

Test Preparation and Influencing Factors

Fasting is generally not required for a serum walnut-specific IgE test.
Antihistamines usually do not interfere with blood IgE testing, although they may affect skin-prick testing or symptoms observed during an oral food challenge.
The test should be interpreted with the timing, reproducibility, and severity of symptoms after walnut exposure.
Total IgE concentration, age, atopic conditions, and other sensitizations may influence interpretation.
Cross-reactivity with related tree nuts or pollen-related allergens may contribute to a positive result without proven clinical walnut allergy.
A positive result indicates sensitization and does not establish allergy or predict reaction severity.
When blood-test findings and the clinical history disagree, a medically supervised oral food challenge may be needed for confirmation or exclusion of allergy.

Synonyms

Walnut-specific IgE
Walnut allergen-specific IgE
Serum walnut IgE
Walnut sIgE
IgE to walnut extract
Juglans regia-specific IgE
T010-IgE Walnut
Walnut component-specific IgE, when directed against individual allergens such as Jug r 1 or Jug r 4