Lab test
Onion Allergy Test – Food Allergies
This page explains the onion allergy test – food allergies, what it measures, and how to order it. An onion allergy test uses a blood sample to check for IgE antibodies that may indicate an allergic reaction to onion.
Lab requirements in Onion Allergy Test – Food Allergies
Here is what you need before ordering and completing the Onion Allergy Test – Food Allergies. Review each item and confirm the details with the collection lab.
- Physician's order
- Included. A physician's order is required for lab testing and is provided for you by our partner's physicians — no referral from your own doctor is needed.
- Fasting
- Some tests require fasting or avoiding certain foods or drinks beforehand. You will be informed when you order — confirm the details with the collection lab.
- Preparation
- No special preparation is usually required, but follow the instructions provided by the collection laboratory. If you take medications, ask the lab or your clinician whether any adjustments…
- Sample & visit
- A blood and/or urine sample is collected; the visit usually takes about 10 minutes.
- Identification
- Bring the lab requisition form from your account. The collection lab may also ask for a government-issued photo ID.
- Turnaround
- 1-3 business days
- Availability
- Our partner lab does not serve ND, RI, NY, NJ, MD or HI. Confirm availability for your location with the collection lab.
Before you go
- Order your test before visiting a lab, then use the requisition form in your account.
- Print the requisition form, or fax it to the lab directly from your account.
- No scheduling is needed — visit the collection lab during its normal business hours.
- A blood and/or urine sample is collected; the visit usually takes about 10 minutes.
- Bring a government-issued photo ID in case the lab requests it.
- Results are posted to your secure account within 1–3 business days.
Requirements are summarized from our partner lab's published policies. Preparation and availability can change — confirm current instructions with the collection lab before your visit.
What this test is
This test measures specific IgE antibodies in the blood that are associated with allergic sensitivity to onion. It is typically used alongside a clinical history to help evaluate whether onion may be triggering allergic symptoms.
What it measures
- Onion-specific IgE — Reflects the level of IgE antibodies that bind to onion proteins.
- Total IgE — Sometimes measured to provide context for allergic tendency, though not specific to onion.
What the test involves
A healthcare professional collects a small blood sample, usually from a vein in your arm, using a standard blood draw. The sample is then sent to a laboratory for analysis.
Why it is often ordered
A clinician may order this test when a person reports symptoms such as hives, itching, or digestive upset after eating onion or foods containing onion. It is often part of a broader evaluation for food allergies.
Preparation
No special preparation is usually required, but follow the instructions provided by the collection laboratory. If you take medications, ask the lab or your clinician whether any adjustments are needed.
How results are reported
Results are reported as a numeric value that is compared with a reference range established by the testing laboratory. Reference ranges can vary between laboratories, so results should be interpreted in the context of your symptoms and clinical history.
Before you go
- Whether any medications you take could affect the test
- The specific reference range used by the laboratory
- How and when results will be shared with you
FAQ
Frequently asked questions
What do the results mean?
A higher level of onion-specific IgE may suggest an increased likelihood of allergy, but it does not confirm a diagnosis on its own. Your clinician will interpret the result along with your symptoms and medical history.
Is this test painful?
The test involves a standard blood draw, which may cause brief discomfort when the needle is inserted. Most people tolerate it well, and the collection takes only a few minutes.
How long does it take to get results?
Results are typically available within a few business days after the sample reaches the laboratory. The exact turnaround time can vary depending on the lab and any additional testing requested.
Can this test tell me if I outgrew an onion allergy?
The test measures antibody levels at a single point in time and cannot by itself show whether an allergy has resolved. Your clinician may repeat testing or use other evaluations to assess changes over time.
Related
Related tests
Locations
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