Biomarker: F212-IgE Mushroom

Overview

F212-IgE Mushroom measures immunoglobulin E (IgE) antibodies in serum that bind to mushroom, generally referring to champignon or Agaricus mushroom extract. IgE is involved in immediate hypersensitivity reactions and can contribute to symptoms such as urticaria, gastrointestinal symptoms, wheezing, and anaphylaxis. A positive or elevated result indicates sensitization, but it does not by itself confirm clinical mushroom allergy or predict reaction severity. The test is clinically useful when interpreted with the patient’s exposure history and symptoms, particularly when evaluating suspected reactions after mushroom ingestion.

Clinical Use Cases

Evaluation of suspected IgE-mediated allergy to edible mushroom.
Investigation of immediate symptoms occurring after mushroom ingestion, including oral allergy symptoms, urticaria, gastrointestinal symptoms, respiratory symptoms, or anaphylaxis.
Supportive testing when skin-prick testing is unsuitable, unavailable, or affected by medications or skin disease.
Assessment of sensitization in patients with suspected reactions to Agaricus bisporus, including button, portobello, and Swiss brown mushrooms.
Adjunctive evaluation of possible cross-sensitization involving other edible mushrooms or molds.
Research assessment of mushroom-specific IgE in documented cases of mushroom hypersensitivity.

Specimen Types

Venous blood.
Serum separated from venous blood.

Measurement Methods

In-vitro allergen-specific IgE immunoassay.
Solid-phase immunoassay, such as an ImmunoCAP-type assay.
Enzyme-linked immunosorbent assay (ELISA) or related quantitative immunoassays.
Historically, radioallergosorbent testing (RAST) was used for allergen-specific IgE measurement.

Test Preparation and Influencing Factors

Fasting is generally not required for a serum-specific IgE test.
Patients should report all medications and supplements. Antihistamines usually do not affect blood-specific IgE results, but medication instructions may vary if skin testing is performed at the same time.
Medications should not be stopped unless directed by a healthcare professional.
Results should be interpreted with the timing, amount, preparation, and type of mushroom consumed and the clinical symptoms that followed.
A positive result indicates sensitization and may occur without clinical allergy. Cross-reactivity with other mushrooms or molds may contribute to a positive result.
The measured IgE concentration does not reliably predict the severity of a future reaction.
A negative result does not completely exclude mushroom allergy, particularly when the tested extract does not represent the relevant mushroom species or preparation.
F212 is an extract-based test and may not identify sensitization to every edible mushroom species or to individual mushroom allergen components.
Mushroom-specific IgE testing has limited availability and should not be used as a screening test in people without a suggestive clinical history.