Biomarker: F058-IgE Squid

Overview

F058-IgE Squid measures immunoglobulin E (IgE) antibodies directed against squid allergens in blood. IgE is involved in immediate hypersensitivity reactions by activating mast cells and basophils after allergen exposure. A high result indicates sensitization to squid but does not, by itself, confirm clinical allergy or predict reaction severity; a low or undetectable result reduces evidence of sensitization but does not completely exclude allergy. The test is clinically useful as an aid to evaluating suspected squid-related food allergy or occupational reactions when interpreted with exposure history, symptoms, and other allergy testing.

Clinical Use Cases

Evaluation of suspected immediate allergic reactions after eating squid.
Investigation of respiratory, ocular, skin, or gastrointestinal symptoms after handling squid or inhaling cooking vapors.
Assessment of possible occupational allergy in seafood-processing or food-service workers.
Supporting evaluation when skin testing is unsuitable because of skin disease, medication use, or concern about a severe reaction.
Investigation of possible cross-sensitization with shrimp and other crustaceans, which has been reported in human studies.
Research on squid allergens, including IgE-binding proteins such as tropomyosin.

Specimen Types

Serum from venous blood.
Serum from capillary blood, when validated by the testing laboratory.
Plasma may be accepted by some assay systems, but specimen requirements are method-specific.

Measurement Methods

Fluorescence-based solid-phase allergen-specific IgE immunoassay.
Enzyme-linked immunosorbent assay (ELISA).
Radioallergosorbent test (RAST), used in earlier clinical studies.
Reverse enzyme immunoassay.
Immunoblotting for research characterization of squid IgE-binding proteins.
Skin-prick or open skin testing with squid extract may complement, but does not replace, serum-specific IgE measurement.

Test Preparation and Influencing Factors

Fasting is generally not required for an allergy blood test.
Patients should report all medications, particularly antihistamines. Medicines should not be stopped unless instructed by a healthcare professional.
The result should be interpreted with the timing and nature of symptoms, the amount and preparation of squid consumed, and whether exposure occurred through ingestion, skin contact, or inhalation.
Different squid species, extracts, and processing methods may expose different allergenic proteins. Cooking can alter allergen availability, so a negative result does not always exclude reactions to a particular preparation.
A positive result indicates immunologic sensitization and does not establish that ingestion will cause symptoms or indicate reaction severity.
Total IgE elevation, smoking, parasitic infection, and other allergic conditions can complicate interpretation of allergy testing.
Cross-reactivity with shrimp and other crustaceans may produce positive results without equivalent clinical reactions to every seafood allergen.
Serum should be separated from cells and handled according to the laboratory’s requirements. Avoiding clotting, leakage, and repeated freeze-thaw cycles is important for specimen integrity.