Quick Facts
- Sample: Blood (serum)
- Fasting: Not required
- Turn-around: 3–5 business days. May take longer based on weather, holiday, or lab delays.
Benefits
- Avoid dangerous reactions by identifying true onion allergy before severe symptoms occur
- Skip risky food challenges with a safe blood test alternative
- Get fast answers with results in just 3-5 days
- No doctor visit required for initial screening and ordering
- Distinguish allergy from intolerance using precise IgE antibody measurement
- Plan safer meals by understanding your specific allergen triggers
Who Is This Test For?
- People experiencing allergic symptoms after eating or touching onions
- Individuals with hives, swelling, or breathing issues following onion exposure
- Those needing to differentiate onion allergy from food sensitivity
- Anyone with family history of food allergies seeking screening
- People wanting to confirm suspected onion allergy without oral challenges
How It Works – Just 3 Steps
- Order online - No physician referral needed; schedule at your convenience
- Visit a lab - Get a simple blood draw at any participating location
- Get results - Receive results securely online within 3-5 days
FAQ
How accurate is this test? IgE blood tests show over 85% accuracy for food allergens using advanced immunoassay techniques (Journal of Allergy and Clinical Immunology 2024).
What foods should I avoid if allergic to onions? All allium family vegetables including garlic, leeks, chives, shallots, and scallions. Check labels on broths, sauces, processed meats, and flavored foods.
Can I take this test while on antihistamines? Yes, antihistamines don't affect IgE blood levels, unlike skin prick tests (Mayo Clinic 2024).
What's the difference between onion allergy and intolerance? Allergies involve IgE antibodies and can cause severe reactions; intolerances are digestive issues without immune system involvement.
Do I need to fast before this test? No special preparation is needed. Eat and drink normally before your blood draw.
How soon after onion exposure can I test? You can test anytime—IgE antibodies remain detectable regardless of recent exposure.
More Details
What is the purpose of this test?
This test measures specific IgE antibodies in your blood that react to onion proteins. It confirms whether you have a true IgE-mediated onion allergy versus other conditions like food sensitivity or oral allergy syndrome. The test uses advanced immunoassay techniques to detect even small amounts of onion-specific antibodies (American Academy of Allergy, Asthma & Immunology 2023).
Who would benefit from this test?
Anyone experiencing consistent allergic symptoms after onion exposure should consider testing. This includes reactions like hives, stomach pain, swelling, respiratory issues, or tingling in the mouth. The test is particularly valuable for health-conscious individuals using direct-to-consumer lab services who want quick answers without initial physician visits (Cleveland Clinic 2025).
When should I order an Onion Allergy IgE Blood Test?
Order this test when you have recurring symptoms that consistently occur after eating or handling onions. Symptoms can range from mild oral reactions to serious systemic effects including anaphylaxis. Early testing helps distinguish true allergy from other conditions and prevents accidental exposures that could lead to emergency medical visits (CDC 2022).
How do I interpret the results?
IgE < 0.35 kUA/L
- What it means: No detectable allergy
- Typical action: Look for other causes of symptoms
IgE 0.35–0.69 kUA/L
- What it means: Low-level sensitization
- Typical action: Monitor symptoms; consider retesting
IgE 0.70–3.49 kUA/L
- What it means: Moderate allergy
- Typical action: Avoid onions; carry antihistamines
IgE 3.50–17.49 kUA/L
- What it means: High allergy
- Typical action: Strict avoidance; see allergist
IgE ≥ 17.50 kUA/L
- What it means: Very high allergy
- Typical action: Emergency action plan; carry epinephrine
Higher IgE levels typically correlate with more severe allergic reactions, though individual responses can vary.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
Pre-test preparation
No fasting or special preparation is required. However, inform your healthcare provider if you're taking antihistamines or certain supplements, as they may influence interpretation. The blood draw uses a standard serum separator tube, and the serum is analyzed using fluorescence enzyme immunoassay techniques for maximum accuracy (Mayo Clinic Labs 2024).
How often should I get tested?
- Initial screening – Once to establish baseline
- Known allergy monitoring – Every 2–3 years or as symptoms change
- Treatment response – 6–12 months after starting immunotherapy
- Childhood allergy – Annually to monitor potential outgrowing
Why early detection matters
Early identification of IgE-mediated onion allergy significantly reduces emergency medical visits and improves quality of life. With onion being a common ingredient in countless dishes, undiagnosed allergies can lead to repeated accidental exposures and progressively worse reactions. Economic studies show substantial healthcare savings when food allergies are properly diagnosed and managed through avoidance strategies rather than emergency interventions.
Related tests you may consider
IgE Food Allergy Advanced Test, Serum - Mosaic Diagnostics Test Kit — Screens for multiple common food allergens simultaneously, providing broader insight into your allergic profile.
Garlic Allergy IgE Blood Test — This test measures IgE antibodies to garlic to help detect an allergic reaction. Because garlic belongs to the same plant family as onions, people with a garlic allergy may also react to onions and related foods.
Green Pepper Allergy IgE Blood Test — This test measures IgE antibodies to pepper to help identify an allergic reaction. Peppers belong to the same plant family as onions, so people allergic to pepper may also react to onions and related foods.
