Gliadin IgE & Wheat IgE w/Rfx

Test Code

GLIADINWHEAT

Quest Code

18737

CPT Codes
86003, 86008

Includes

If Wheat (f4) IgE is ≥0.10 kU/L, then Wheat Component Tri a 14 (f433) IgE will be performed at an additional charge (CPT code(s): 86008).

Preferred Specimen

2 mL serum

Minimum Volume

1 mL

Transport Container

Serum separator tube (SST)

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 14 days
Refrigerated: 14 days
Frozen: 30 days

Methodology
Immunoassay (IA)

Reference Range

See Laboratory Report

Clinical Significance

Testing for IgE antibodies to wheat using whole wheat extract (f4) has high sensitivity but low specificity due to cross-reactivity with proteins also present in rye and barley, as well as grass pollen. Wheat component testing may help manage patients with suspected wheat allergy. Positive results with Tri a 14 (f443), a protein with little or no cross-reactivity with grass pollen, may help to confirm true sensitization to wheat. On the other hand, some gluten proteins may not be well-represented in wheat extract. Gliadins are wheat proteins which are poorly soluble in saline and require extraction using alcohol. Positive results with gliadin (f98) indicate sensitization to wheat despite negative results for wheat extract.

Performing Laboratory

Quest Diagnostics LLC

200 Forest Street, 3rd Floor, Suite B

Marlborough, MA 01752-3023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.