Biomarker: F255-IgE Plum

Overview

F255-IgE Plum measures immunoglobulin E (IgE) antibodies in serum that bind to plum (Prunus domestica) allergens. IgE is involved in immediate hypersensitivity reactions by activating mast cells and basophils, which can release inflammatory mediators after allergen exposure. A detectable or elevated result indicates sensitization to plum and may support evaluation of IgE-mediated reactions, but it does not by itself confirm clinical allergy or predict reaction severity. The test is clinically useful when interpreted with the patient’s exposure history, symptoms, and, when necessary, supervised oral food-challenge results.

Clinical Use Cases

Supporting evaluation of suspected immediate allergy to plum.
Identifying plum as a possible trigger in patients with food-related urticaria, angioedema, gastrointestinal symptoms, respiratory symptoms, or anaphylaxis.
Evaluating possible cross-sensitization among related Rosaceae fruits, such as peach, apricot, cherry, apple, and plum.
Supporting decisions about additional allergy evaluation, including skin-prick testing or a medically supervised oral food challenge.
Documenting sensitization in clinical research involving fruit allergy and IgE-mediated food allergy.

Specimen Types

Serum collected from venous blood.
Whole blood may be used for specialized research assays such as basophil activation testing, but this is not the usual specimen for routine F255-specific IgE measurement.

Measurement Methods

Fluorescence enzyme immunoassay using an allergen-coated solid phase, such as an ImmunoCAP-type assay.
Other validated in-vitro specific-IgE immunoassays, including enzyme-linked immunosorbent assay formats.
Skin-prick or prick-to-prick testing with plum may be used as a complementary, in-vivo assessment, but it does not measure serum F255-IgE directly.
Component-resolved testing may evaluate IgE to individual plum proteins, such as lipid-transfer proteins, where clinically available.

Test Preparation and Influencing Factors

Fasting is generally not required for a serum-specific IgE test.
Antihistamines usually do not interfere with serum-specific IgE measurement, although they can suppress skin-prick-test responses.
Results should be interpreted with the timing, amount, and form of plum exposure and the patient’s symptoms.
A positive result indicates sensitization, not necessarily clinical allergy; false-positive or clinically insignificant results can occur.
Higher specific-IgE concentrations may increase the likelihood of clinical reactivity, but concentration does not reliably predict reaction severity.
Very high total IgE concentrations, including those associated with severe atopic dermatitis, may increase nonspecific binding and complicate interpretation.
Results from different assay platforms and laboratories may not be directly interchangeable.
Broad food-allergen panels can identify clinically irrelevant sensitizations and should be guided by the clinical history.
A negative result lowers the likelihood of IgE sensitization but does not absolutely exclude food allergy.
A medically supervised oral food challenge may be required when the test result and clinical history are discordant.