Walnut, Allergen IgE, Component

Test Codes

EPIC: LAB3624, Beaker: EWALC, CHW: LAB3624

Department

Send Outs

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Physician Office/Draw Specimen Preparation

Let specimen clot for 30 minutes then centrifuge to separate serum from cells within 2 hours of collection. Transfer serum to plastic transport tube and maintain refrigerated at (2-8°C or 36-46) prior to transport.

Preparation for Courier Transport

Transport: 3.0 mL serum, refrigerated at (2-8°C or 36-46°F). (Minimum: 2.0 mL)

Rejection Criteria

Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot for 30 minutes then centrifuge to separate serum from cells within 2 hours of collection. Transfer serum to plastic transport tube and maintain refrigerated at (2-8°C or 36-46) prior to transport.

Transport: 3.0 mL serum, refrigerated at (2-8°C or 36-46°F). (Minimum: 2.0 mL)

Storage

Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Aliquot for longer storage
Specimen Storage in Department Prior to Disposal: 30 days

Specimen retention time is determined by the policy of the reference laboratory. Contact the Send Outs Laboratory with any questions.

Laboratory

Sent to Corewell Health Reference Laboratory, Grand Rapids, MI.

Performed

Monday – Friday.
Results available in 1-3 days.

Reference Range

Test Methodology

Clinical Utility

IgE antibodies to rJug r 1 (Walnut Storage Protein) are associated with systemic reactions to walnuts.

IgE antibodies to rJug r 3 (Walnut LTP) are associated with local as well as systemic reactions to walnuts.

Component testing for Walnut must be ordered as follow-up to whole allergen results. They are not available as reflex tests. Patient specimens are stored frozen for 30 days.

Component testing measures IgE antibodies to individual proteins unlike whole allergen testing which measures the presence of specific immunoglobulin E (sIgE) antibodies to a combination of allergenic and non-allergenic proteins. This next generation testing identifies the source of sensitization and helps the clinician assess the risk of systemic reaction.

Results of component testing can assist with patient selection for oral food challenge as well as possible management recommendations such as immunotherapy and/or allergen avoidance/food elimination. Because of the diagnostic and management complexities associated with food allergy, referral to an allergy and immunology specialist should be considered when evaluating a patient with suspected food allergies.

CPT Codes

86008

Contacts

Last Updated

4/27/2026