Biomarker: F182-IgE Lima Bean

Overview

F182-IgE Lima Bean measures immunoglobulin E (IgE) antibodies in serum that bind to lima bean (Phaseolus lunatus) proteins. IgE is involved in immediate hypersensitivity reactions, including food-allergic responses. A detectable or elevated result indicates sensitization to lima bean but does not by itself confirm clinical allergy or predict reaction severity. Lima bean sensitization appears uncommon and may reflect cross-reactivity with other legumes or related plant allergens; current evidence on lima-bean-specific allergens is limited.

Clinical Use Cases

Supports evaluation of suspected immediate-type allergy after lima bean ingestion or exposure.
Helps assess sensitization in patients with suspected allergy to multiple legumes.
Contributes to evaluation of possible cross-reactivity with peanut, soybean, other legumes, or mesquite pollen.
May support investigation of occupational respiratory symptoms associated with lima bean dust or vapors.
Helps guide further assessment with clinical history, skin-prick testing, supervised elimination, or oral food challenge.
May be used in research evaluating legume allergen sensitization and IgE cross-reactivity.

Specimen Types

Serum or plasma obtained from venous blood.
Whole blood may be used for some research-based cellular assays, but routine F182-IgE testing is generally performed on serum.

Measurement Methods

Allergen-specific IgE immunoassay using lima bean extract.
Fluorescence enzyme immunoassay or comparable solid-phase immunoassay.
Enzyme-linked immunosorbent assay in research settings.
Immunoblotting or immunoblot inhibition assays for research characterization of IgE-binding proteins and cross-reactivity.
Skin-prick testing and oral food challenge are complementary clinical procedures, not measurements of serum F182-IgE.

Test Preparation and Influencing Factors

Fasting is generally not required for an allergen-specific IgE blood test.
Patients should report antihistamines, corticosteroids, biologic medicines, and supplements to the ordering clinician.
Medicines should not be stopped unless specifically directed by a health care professional.
Recent exposure to lima bean does not usually require delaying blood collection, although timing may be considered when interpreting results.
A positive result indicates sensitization and must be interpreted with symptoms, exposure history, and clinical examination.
Cross-reactive IgE may produce a positive result without clinically relevant lima bean allergy.
Total IgE, smoking, parasitic infection, and other allergic conditions may influence interpretation of IgE testing.
The concentration of specific IgE does not reliably predict the severity of a future reaction.
Oral food challenges should be performed only under specialist supervision because they can provoke severe reactions.