Walnut-Food Components, IgE, Serum

Casandra

Casandra Test Code MC47603Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID BLWXCPT Code 86008

Walnut-Food Components, IgE, Serum

Clinical Use

Use

The Walnut-Food Components, IgE, Serum test is used for evaluating patients suspected of having a walnut-food allergy, particularly to the major allergen components, Jug r 1 and Jug r 3. Allergies to tree nuts, including walnuts, are prevalent and can cause severe reactions that appear rapidly after ingestion. Tree nut allergies are among the most dangerous, capable of causing anaphylaxis, and are often persistent throughout a patient's lifetime. Jug r 1 is a major component that induces systemic allergic reactions to walnuts and has a high positive predictive value for diagnosing walnut allergy. Jug r 3 is also a major allergen associated with severe allergic reactions. Both components are important for determining walnut allergy, and cross-reactivity with other nut allergens is possible.

Special Instructions

This test is only orderable as a reflex. If the total walnut-food IgE result is 0.10 kU/L or more, further testing for the walnut components Jug r 1 and Jug r 3 is performed at an additional charge. The test utilizes a fluorescent enzyme immunoassay (FEIA) method and is performed on weekdays from Monday through Friday at Mayo Clinic Laboratories - Rochester Superior Drive.

Limitations

Negative results for IgE antibodies to walnuts and its components do not exclude clinically significant allergic responses. Positive results suggest sensitization but are not definitive for allergy diagnosis. Specific IgE testing may not be useful in patients previously treated with immunotherapy or those for whom allergen identification does not affect management. False positives can occur due to nonspecific binding, especially in patients with high serum IgE levels.

Test Details

FDA Approved