Onion, IgE, Serum
Use
The Onion IgE test is useful for establishing a diagnosis of an allergy to onions by detecting specific IgE antibodies in the serum. It helps in defining the allergen responsible for eliciting allergic signs and symptoms like anaphylactic episodes. The test also aids in confirming sensitization before starting immunotherapy and investigating the specificity of allergic reactions to various allergens such as insect venom, drugs, or chemicals. However, it is not considered useful for assessing residual clinical sensitivity after immunotherapy or when allergen specificity does not impact medical management.
Special Instructions
When ordering, consider completing the Allergen Test Request form (T236) if not ordering electronically. Ensure that specimens are correctly collected, centrifuged, and aliquoted as per instructions to avoid diagnostic confusion. Note that some individuals may have high IgE levels without significant clinical allergen sensitivity, and false positives can occur in cases of extremely high serum IgE levels.
Limitations
The test may yield false-positive results in patients with markedly elevated serum IgE levels (>2500 kU/L) due to nonspecific IgE binding. The presence of IgE antibodies does not always correlate with clinical symptoms, as some patients with detectable IgE levels may not exhibit significant sensitivities. Interpretation should be done in the context of clinical history and presentation.
FDA ApprovedNew York Approved
Methodology
Immunoassay (FEIA)
Biomarkers
LOINC Codes
- 6193-7
- 6193-7
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL for every 5 allergens requested
Minimum Volume
0.3 mL for 1 allergen
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Grossly hemolyzed or lipemic specimens may be rejected.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 14 days |
| Frozen | 90 days |