Biomarker: F424-IgE Ara h 3
Overview
F424-IgE Ara h 3 measures serum immunoglobulin E (IgE) antibodies specific to Ara h 3, a peanut seed-storage protein in the 11S globulin, or legumin, family. Ara h 3 is a heat-stable peanut allergen that can bind IgE in people sensitized to peanut. A detectable result indicates sensitization, but does not by itself confirm clinical peanut allergy or predict reaction severity. The test may complement peanut extract-specific IgE, skin-prick testing, clinical history, and, when appropriate, a medically supervised oral food challenge.
Clinical Use Cases
- Assess sensitization to a specific peanut protein as part of component-resolved allergy testing.
- Support evaluation of suspected IgE-mediated peanut allergy when interpreted with clinical history and other allergy tests.
- Help characterize the pattern of peanut allergen sensitization, particularly alongside Ara h 1, Ara h 2, Ara h 6, Ara h 8, and whole-peanut-specific IgE.
- Support clinical or epidemiologic research on peanut allergy, allergen profiles, and treatment-related changes in allergen-specific IgE.
- Assist specialist assessment when whole-peanut testing and the clinical history are discordant.
Specimen Types
- Serum, usually collected by venipuncture.
- Plasma may be accepted by some assay platforms, subject to the laboratory’s validated specimen requirements.
Measurement Methods
- Quantitative or semiquantitative allergen-specific IgE immunoassay using recombinant Ara h 3, commonly reported in kUA/L or equivalent assay units.
- Solid-phase immunoassays, including fluorescence- or enzyme-based platforms.
- Component-resolved diagnostics that measure IgE to individual allergen molecules rather than only to whole-peanut extract.
- Research methods may include ELISA and immunoblot-based IgE-binding assays, but these are not interchangeable with standardized clinical testing.
Test Preparation and Influencing Factors
- No fasting or other special preparation is generally required for an allergy blood test.
- Tell the healthcare professional about all medicines and supplements. Do not stop antihistamines or other medicines unless specifically instructed.
- A positive result indicates IgE sensitization, not necessarily symptomatic peanut allergy. Interpretation requires a compatible history of exposure and symptoms.
- The concentration of Ara h 3-specific IgE does not independently establish the severity of a future reaction.
- Results depend on the assay, allergen preparation, reporting units, and laboratory cutoff. Values from different platforms should not be compared directly without appropriate validation.
- Recent exposure to peanut is not generally required before blood collection.
- A supervised oral food challenge remains the reference clinical procedure when the diagnosis cannot be established from history and testing.
Synonyms
- Ara h 3-specific IgE
- Peanut component Ara h 3 IgE
- rAra h 3-specific IgE
- F424
- f424
- Ara h 3 (glycinin)
- Ara h 3 (11S globulin)
- Peanut legumin-specific IgE
- Ara h 3.01 and Ara h 3.02, referring to recognized Ara h 3 isoforms or related allergen forms.
This information is provided for general educational purposes and is not medical advice. Biomarker information may describe testing methods, measurements, or interpretations that vary by laboratory or specific test. For details about a particular lab test, including biomarkers measured, specimen type, collection requirements, preparation, and turnaround time, please refer to the individual test description. Talk with a licensed health care provider about your results.
