Onion Allergy Test
This page explains the onion allergy test, what it measures, and how to arrange it. An onion allergy test is a blood test that checks whether your immune system reacts to proteins found in onions. It is usually ordered when someone has symptoms such as itching, hives, or stomach upset after eating onions or foods containing onion powder.
- Sample type
- blood
- Category
- Allergy
- Turnaround
- 1-3 business days
- Price
- $49
- Referral
- Not required
An onion allergy test is a blood test that checks whether your immune system reacts to proteins found in onions. It is usually ordered when someone has symptoms such as itching, hives, or stomach upset after eating onions or foods containing onion powder.
What it measures
- Onion-specific IgE — Antibodies made by the immune system that can recognize onion proteins.
- Total IgE — A general measure of allergic antibody levels in the blood.
- Allergen component profile — A closer look at which specific onion proteins may trigger a reaction.
Who it is for
A doctor or allergist typically orders this test when a person reports symptoms after eating onions or when other allergy tests need confirmation. It may also be used to help tell an onion allergy apart from other food reactions.
Preparation
No fasting or special preparation is usually needed. Tell your clinician about any medicines you take, because some antihistamines can affect allergy test results.
Results and what they mean
Results are reported as a level or class for onion-specific IgE, along with a total IgE value. A clinician interprets these numbers together with your symptoms and history, because a positive result alone does not always mean you have an allergy. This is general information, not medical advice.
How to order this test
- Choose the test and place a confidential order online.
- Select a certified collection site and pick a time that suits you.
- Have your specimen collected — most draws take only a few minutes.
- Review results in a secure portal, typically within 1–3 days.
Preparation, hours, and pricing vary by site; confirm details directly with the lab before your visit.
Frequently asked questions
Does a positive result mean I am allergic to onions?
Not always. A positive result shows your immune system has made antibodies to onion proteins, but only a clinician can decide whether that means a true allergy based on your symptoms.
Do I need to avoid onions before the test?
No. You do not need to change your diet before this blood test unless your clinician tells you otherwise.
How long does it take to get results?
Results are usually available within 1 to 3 business days.
Can this test tell me how severe a reaction will be?
No. The test helps show whether you are sensitized to onions, but it cannot predict how mild or severe a future reaction might be.