Biomarker: F015-IgE White Bean

Overview

F015-IgE White Bean measures immunoglobulin E (IgE) antibodies in blood that recognize proteins from white bean, generally Phaseolus vulgaris. IgE is involved in immediate-type allergic reactions, including hives, gastrointestinal symptoms, respiratory symptoms, and anaphylaxis. A detectable result indicates sensitization to the tested white-bean extract, but it does not by itself confirm clinical allergy or predict reaction severity. The test is clinically useful as an adjunct to an allergy-focused history and, when necessary, supervised oral food challenge.

Clinical Use Cases

• Evaluation of suspected IgE-mediated allergy to white bean.
• Assessment of immediate symptoms occurring after eating white bean or foods containing white-bean ingredients.
• Support for food-allergy evaluation when skin-prick testing is unsuitable because of extensive skin disease, dermographism, or medications that suppress skin reactivity.
• Identification of sensitization to white bean alongside other suspected legumes when supported by the clinical history.
• Research assessment of white-bean-specific IgE responses in individuals with atopic disease or suspected legume allergy.

Specimen Types

• Venous blood, processed as serum.
• Serum stored refrigerated or frozen according to the testing laboratory’s requirements.

Measurement Methods

• Fluorescence enzyme immunoassay (FEIA), including allergen-coated solid-phase systems such as ImmunoCAP.
• Enzyme-linked immunosorbent assay (ELISA).
• Chemiluminescent immunoassay.
• Radioallergosorbent testing (RAST), an older method that has largely been replaced by newer immunoassays.
• Immunoblotting or western blotting, primarily for research or allergen characterization rather than routine clinical diagnosis.

Test Preparation and Influencing Factors

• Fasting is generally not required for a serum-specific IgE blood test.
• Most antihistamines do not need to be stopped for serum-specific IgE testing, unlike skin-prick testing. Medication changes should be discussed with the ordering clinician.
• Results should be interpreted with the timing, amount, preparation, and reproducibility of symptoms after white-bean exposure.
• Cooking and processing can alter the proteins recognized by IgE; therefore, results based on one extract may not represent reactivity to every white-bean preparation.
• Higher specific-IgE concentrations generally increase the likelihood of clinical reactivity, but thresholds are not reliably established for white bean and results do not predict reaction severity.
• A positive result indicates sensitization, not necessarily symptomatic food allergy. A negative result also does not completely exclude allergy when the clinical history is strongly suggestive.
• Broad food-allergen panels can produce clinically irrelevant positive results and should be guided by the patient’s history.
• A supervised oral food challenge may be required when the history and test results do not establish the diagnosis.

Synonyms

• White bean-specific IgE
• White-bean allergen-specific IgE
• White bean sIgE
• Phaseolus vulgaris-specific IgE
• F15 white bean IgE
• Allergen-specific immunoglobulin E to white bean
• White bean allergy blood test

Further Reading

• Food Allergy Testing — MedlinePlus, U.S. National Library of Medicine.
• Allergy Blood Test — MedlinePlus, U.S. National Library of Medicine.
• Diagnostic Evaluation of Food-Related Allergic Diseases — Allergy, Asthma & Clinical Immunology.
• Overview of Food Allergy Diagnosis — National Institutes of Health, PMC.
• Optimizing the Diagnosis of Food Allergy — Journal of Asthma and Allergy.
• A Case of White Bean Allergy — Asia Pacific Allergy.
• Effect of Heat and Enzymatic Treatments on Human IgE and Rabbit IgG Sensitivity to White Bean Allergens — PubMed, U.S. National Library of Medicine.
• Guidelines for the Diagnosis and Management of Food Allergy in the United States — National Institute of Allergy and Infectious Diseases.