Food allergy testing typically focuses on nine major allergens that account for about 90% of all allergic reactions: milk, eggs, peanuts, tree nuts, wheat, soy, fish, shellfish, and sesame. Beyond these core foods, your allergist may test for dozens of additional items depending on your symptoms, diet, and history. The specific foods on your panel aren’t random. They’re chosen based on what you eat, what reactions you’ve had, and sometimes your age and where you live.
The Big 9 Allergens
The U.S. Food Allergen Labeling and Consumer Protection Act originally identified eight major allergens, with sesame added in 2023 to form what’s now called the “Big 9.” These are the foods most likely to appear on any standard allergy test panel:
- Cow’s milk
- Eggs
- Peanuts
- Tree nuts (almonds, walnuts, pecans, cashews, pistachios, and others)
- Wheat
- Soy
- Fish (bass, flounder, cod, salmon, and others)
- Shellfish (shrimp, crab, lobster)
- Sesame
While more than 160 foods can trigger allergic reactions, these nine cause the overwhelming majority of serious cases. Most allergists start here before expanding the panel.
What’s Tested in Children vs. Adults
Eggs, milk, and peanuts are the most common triggers in children, so pediatric panels almost always include these three prominently. The good news for parents is that allergies to milk, egg, wheat, and soy often resolve during childhood. Allergies to peanuts, tree nuts, fish, and shellfish are more likely to be lifelong.
For adults, testing panels tend to shift toward shellfish, fish, tree nuts, and fruits or vegetables that cause reactions. Adults are also more likely to develop new allergies to foods they’ve eaten for years, so the panel often reflects their recent dietary history rather than a standard checklist.
Fruits, Vegetables, and Spices
If you have hay fever or seasonal allergies, your allergist may test for a wider range of plant-based foods. This is because proteins in certain fruits and vegetables closely resemble pollen proteins, triggering what’s called oral allergy syndrome. The list of potential cross-reactive foods is surprisingly long:
- Fruits: apple, apricot, cherry, peach, pear, plum, banana, kiwi, orange, cantaloupe, honeydew, watermelon, tomato
- Vegetables: carrot, celery, bell pepper, cucumber, zucchini, white potato, broccoli, cabbage, cauliflower, onion, garlic
- Nuts and legumes: hazelnut, almond, peanut, soybean
- Spices: fennel, coriander, caraway, aniseed, black pepper
Not everyone with pollen allergies will be tested for all of these. Your allergist narrows the list based on which specific pollens you react to and which foods seem to cause symptoms. For instance, Mayo Clinic Labs offers a fruit-specific panel that tests apple, banana, peach, and pear as a group.
Seeds and Less Common Allergens
Seeds have become a growing concern as foods like chia, flax, and sunflower seeds have gained popularity. Sesame is now part of the Big 9, but other seed allergies remain rare and are typically only tested when your history suggests a reaction. Poppy, flax, pumpkin, mustard, sunflower, and chia seeds have all been reported to cause allergic reactions, though published cases are limited.
Mustard seed allergy is notable because testing with raw mustard extract is more reliable than using commercial test extracts or blood tests. This is one of several situations where fresh food applied directly to the skin gives better results than standardized panels. In Europe, mustard and celery are recognized as major allergens and appear on testing panels more routinely than in the U.S.
Skin Prick Tests vs. Blood Tests
The two main approaches to food allergy testing offer different options in terms of how many foods can be checked at once. Skin prick testing involves placing tiny drops of allergen extract on your forearm or back and lightly pricking the skin. Results appear within about 15 to 20 minutes as small raised bumps at the sites where you’re allergic. A typical session can test between 36 and 54 or more allergens at once.
Blood tests (serum IgE testing) measure the levels of allergy-specific antibodies in your blood. They’re useful when skin testing isn’t practical, for example if you’re taking antihistamines that can’t be stopped, if you have widespread eczema, or if the specific allergen you need isn’t available as a skin prick extract. Blood tests can check for a broader range of foods since they aren’t limited by what’s available in extract form.
Skin prick tests cost less and give faster results. Blood tests are more flexible in terms of what can be tested and don’t carry any risk of triggering a reaction during the test itself.
Component Testing for Severity
Standard allergy tests tell you whether you react to a whole food, but newer component testing goes deeper. It identifies which specific proteins within a food trigger your immune response, and this matters because different proteins carry different risks.
For peanut allergy, reacting to certain storage proteins (known in clinical shorthand as Ara h 2 and Ara h 6) is associated with more severe reactions and stronger immune cell activation. Reacting to a different peanut protein (Ara h 8) is linked to persistent allergy but not necessarily severe reactions. In southern Europe, yet another protein (a lipid transfer protein) acts as a marker for systemic, more dangerous responses.
The same principle applies to other foods. For egg allergy, children with high levels of antibodies against a protein called ovomucoid are more likely to have persistent allergy that doesn’t resolve with age. For milk allergy, reacting to casein (the protein that survives heating) means you’re less likely to tolerate baked milk products and more likely to stay allergic longer. Component testing can also flag whether a child with milk allergy might react to beef, since the two share a related protein.
Component testing isn’t routine for everyone. It’s most useful when your allergist needs to predict whether you’ll outgrow an allergy, whether you can safely eat a food in baked form, or how cautious you need to be about avoiding trace exposures.
How Your Allergist Chooses the Panel
The foods selected for your test aren’t pulled from a universal checklist. Your allergist considers your age, the specific symptoms you’ve had, when and where reactions occurred, your diet, the season, and your history of other allergic conditions like eczema or asthma. A toddler with hives after eating scrambled eggs will get a different panel than an adult who gets an itchy mouth from raw apples every spring.
This is also why testing for every possible food “just to see” isn’t recommended. Allergy tests can produce false positives, meaning the test shows a reaction to a food that you actually tolerate fine. Testing foods you eat regularly without problems leads to unnecessary worry and pointless dietary restrictions. The most accurate results come from targeted testing guided by a real clinical history of reactions.
IgG “Intolerance” Tests Are Not the Same
If you’ve seen mail-order kits that test dozens or even hundreds of foods for “sensitivities” or “intolerances,” those are measuring a completely different antibody called IgG. This is not the same as the IgE antibody that drives true allergic reactions. IgE antibodies cause the immediate symptoms of food allergy: hives, swelling, breathing difficulty, anaphylaxis. IgG antibodies, on the other hand, are a normal part of your immune system’s response to foods you eat regularly. Having IgG antibodies to a food generally reflects exposure, not a problem.
Major allergy organizations do not endorse IgG food panels for diagnosing allergies or intolerances. Legitimate food allergy testing measures IgE through skin prick or blood tests, and when results are ambiguous, the gold standard is a supervised oral food challenge where you eat the food under medical observation.