Biomarker: F044-IgE Strawberry

Overview

F044-IgE Strawberry measures strawberry-specific immunoglobulin E (IgE) antibodies in blood, indicating immune sensitization to strawberry proteins. IgE is involved in immediate-type allergic reactions through activation of mast cells and basophils. A high result may indicate sensitization, but it does not by itself confirm clinical strawberry allergy or predict reaction severity; a low or undetectable result reduces the likelihood of IgE-mediated allergy but does not completely exclude it. The test is clinically useful when interpreted with the patient’s reaction history and, when necessary, a medically supervised oral food challenge.

Clinical Use Cases

Supports evaluation of suspected IgE-mediated strawberry allergy.
Helps assess sensitization in patients with symptoms such as oral itching, urticaria, angioedema, gastrointestinal symptoms, wheezing, or anaphylaxis after strawberry exposure.
May support evaluation of pollen-food allergy syndrome, particularly when symptoms occur mainly after eating fresh strawberry.
Helps guide decisions about further assessment, dietary avoidance, or a supervised oral food challenge.
May be used in clinical research examining strawberry sensitization and cross-reactivity with plant allergens.
Helps distinguish sensitization from clinically relevant allergy when combined with clinical history and other testing. A positive specific-IgE result alone is not diagnostic.

Specimen Types

Venous blood, with serum or plasma used for in-vitro specific-IgE measurement.
Capillary blood may be used in some validated testing settings.
Skin-prick testing with strawberry extract or fresh strawberry is an alternative in-vivo assessment, but it is not the specimen used for the F044-IgE blood measurement.

Measurement Methods

In-vitro allergen-specific IgE immunoassay using strawberry allergen extract.
Enzyme-linked or fluorescence-based immunoassays, depending on the laboratory platform.
Older methods include radioallergosorbent testing, or RAST, although modern immunoassays are more commonly used.
Skin-prick testing with commercial strawberry extract or fresh-food prick-by-prick testing may be used as a complementary method.
Component-resolved testing may assess IgE to individual strawberry allergen components, such as Fra a 1 or Fra a 3, where clinically available, but this is distinct from whole-strawberry F044-IgE testing.

Test Preparation and Influencing Factors

No fasting or special preparation is usually required for a strawberry-specific IgE blood test.
Patients should report all prescription medicines, over-the-counter medicines, vitamins, and supplements.
Antihistamines generally do not affect serum-specific IgE measurement, but they can suppress skin-prick test responses. They should only be withheld if directed by the clinician.
Total IgE elevation, atopic dermatitis, other allergic diseases, smoking, and parasitic infection may complicate interpretation of allergy blood-test results.
Recent exposure to strawberry is not generally required before blood collection.
Age, clinical history, underlying atopy, assay calibration, and the laboratory’s reporting units and reference categories affect interpretation.
A positive result indicates sensitization rather than definite clinical allergy, and the measured concentration does not reliably predict reaction severity.
Cross-reactivity with related plant allergens may contribute to a positive result or to symptoms consistent with pollen-food allergy syndrome. Strawberry contains recognized allergen families including PR-10-related proteins and lipid-transfer proteins.
Oral food challenges require separate preparation and medical supervision; antihistamines may need to be stopped beforehand because they can mask early symptoms.