Onion

The Onion test is a blood test tailored to detect specific immunoglobulin E (IgE) antibodies in response to onion proteins (antigens). This test helps identify onion and onion-based food allergies.

Onions are a common kitchen staple, adding bold flavor and aroma to dishes, while being rich in vitamins, minerals, and antioxidants that support a healthy diet. However, some individuals can have allergic reactions to onions, causing stomach problems, skin rashes, or more serious reactions. The Onion test helps diagnose an onion allergy by checking for specific antibodies (IgE) that the body makes against proteins present in onions. This test helps confirm if the immune system is mistakenly treating onions as a threat and causing an allergy.

The Onion test is recommended when individuals experience symptoms such as itching, swelling, or discomfort in the mouth or throat, skin rashes, nausea, stomach cramps, or diarrhea after eating raw or cooked onions. It can help distinguish onion allergies from other conditions like oral allergy syndrome (OAS),  a type of food allergy that causes allergic reactions in the lips, mouth, and throat upon eating certain raw fruits and vegetables. 

A positive test result for onion-specific IgE antibodies means there is an ongoing onion allergy, and avoiding onions is usually recommended to prevent reactions. If the result is negative, more tests may be needed to find other causes for the symptoms, such as food sensitivities that don’t involve IgE antibodies.

No special preparation is required for the Onion test. However, it is important to inform the doctor about any medications (such as antihistamines) or supplements being taken, as these may affect the test results. Lab test results can vary depending on the specific test method and allergens used, so they should be interpreted alongside clinical symptoms.