Biomarker: F447-IgE Ara h 6

Overview

F447-IgE Ara h 6 measures serum immunoglobulin E (IgE) antibodies directed against Ara h 6, a peanut allergen and 2S albumin seed-storage protein. Detection indicates sensitization to this peanut component, but it does not by itself establish clinically relevant peanut allergy or predict reaction severity. High levels may support a diagnosis of peanut allergy when consistent with a compatible clinical history, while a low or undetectable result reduces evidence of Ara h 6 sensitization but does not exclude allergy to other peanut components. The test is used as part of component-resolved diagnostics, particularly when peanut allergy is suspected and results for Ara h 2 or whole-peanut extract are inconclusive.

Clinical Use Cases

Support evaluation of suspected IgE-mediated peanut allergy in patients with a compatible history.
Identify sensitization to the peanut component Ara h 6.
Complement testing for whole-peanut extract and other peanut components, especially Ara h 2.
Help distinguish sensitization patterns associated with primary peanut allergy from some cross-reactive patterns.
Assist clinical risk assessment when interpreted with symptoms, other allergy tests, and, when necessary, a medically supervised oral food challenge.
Support research on component-resolved diagnosis and the relationship between Ara h 6 sensitization and clinical peanut reactions.

Specimen Types

Venous blood.
Serum, typically separated from venous blood.
Plasma may be used by some validated assay systems, but specimen requirements are platform-specific.

Measurement Methods

Allergen-specific immunoassay using purified native or recombinant Ara h 6.
Singleplex quantitative specific-IgE immunoassays, commonly reported in kUA/L or an equivalent standardized unit.
Multiplex component-resolved immunoassays that measure IgE to multiple peanut components simultaneously.
Research enzyme-linked immunosorbent assays (ELISAs) using Ara h 6 antigen.

Test Preparation and Influencing Factors

Fasting is generally not required for a serum specific-IgE blood test.
Patients should report all medications and supplements. Medication changes should be made only on the advice of the ordering clinician.
Antihistamines generally do not prevent collection or analysis of a blood specific-IgE test, unlike skin-prick testing.
Results should be interpreted with the timing, amount, form of peanut consumed, symptoms, and reproducibility of prior reactions.
A positive result indicates sensitization and does not independently confirm clinical allergy.
A negative or low result for Ara h 6 does not exclude peanut allergy caused by sensitization to Ara h 2, Ara h 1, Ara h 3, Ara h 8, Ara h 9, or other peanut allergens.
Assay platforms, component preparations, reporting units, and decision thresholds may differ; results should not be compared across methods without appropriate validation.
Oral food challenges remain important when clinical history and laboratory findings are discordant and must be performed under appropriate medical supervision.