Food Allergy Testing

Getting tested for food allergies is important for preventing unnecessary avoidance of food and reducing your risk of potentially life-threatening allergic reactions.

What are the symptoms of food allergies?

Common symptoms of food allergies according to the American Academy of Allergy, Asthma & Immunology (AAAAI) include:

• Tingling or itching in the mouth
• Swelling of the lips, tongue, or throat
• Hives or rash
• Nausea or vomiting
• Diarrhea or abdominal pain
• Difficulty breathing or wheezing
• Dizziness or fainting
• Anaphylaxis (a severe, life-threatening allergic reaction that can affect several systems in the body)

It is important to note that not all food allergies cause the same symptoms, and the severity of symptoms can vary from person to person. In some cases, symptoms may not appear until several hours after consuming the allergenic food, according to the AAAAI.

What does animal and food allergy testing consist of?

Food allergy testing consists of an allergist or other medical provider assessing your medical history, in addition to allergy testing techniques such as:

• Skin testing
• Blood testing
• Oral challenge testing

Types of food allergy tests

Skin prick test

The skin prick test evaluates the response of your skin to the presence of a food allergen. According to the NLM, the allergist will place a small amount of the food allergen into the skin on your forearm or back. Using a needle or plastic device, the allergist will slightly scratch or cut the skin surface allowing a very small amount of the allergen to enter the skin. You are unlikely to feel any pain, and there is no bleeding.

If you or your child have been sensitized to the food, your body will react and produce a bump at the center of red itchy skin, known as a wheal. The size of the wheal indicates the likelihood of a food allergy, reports the NLM. However, the size of the wheal does not accurately predict a food allergy. The absence of a wheal is an indication that you are most likely not allergic to the food.

Blood test

A food allergy blood test evaluates the levels of inflammatory compounds formed by your immune system (known as IgE antibodies) after exposure to an allergen. A healthcare professional will use a small needle to collect blood into a test tube from a vein in your arm or hand—then send the blood for laboratory testing. According to the American College of Allergy, Asthma, and Immunology (ACAAI), a blood draw lasts for a few minutes, and you may experience mild discomfort when the needle is inserted and removed from the vein.

Oral food challenge (OFC) test

An oral food challenge test (OFC) can be done in several ways. According to the NLM, the OFC can be done in an open challenge with both you and the allergist aware of the food you are eating, a single-blind challenge when you are unaware of the food, and a double-blinded placebo-controlled challenge with both you and the allergist unaware of the food you are eating. You and your child will be less likely to have a double-blinded placebo OFC challenge time because it takes a long time and is less commonly done.

Who should get a drug allergy test?

You should consider getting a food allergy test for you and your child if you develop symptoms of an allergic reaction typically within two hours after exposure or eating certain types of food.

You may also consider food allergy testing if you or your child have risk factors for food allergies. According to the AAAAI, your risk for food allergies is increased with the following:

• An immediate family member has any allergic disease
• Severe eczema: Genetic mutations in the filaggrin gene have been associated with both food allergy and increased eczema severity
• Asthma
• Other food allergies

How to get a food allergy test

Food allergy tests are provided by healthcare providers at clinics and urgent care centers. However, the AAAAI recommends getting tested by an allergist (a doctor with expertise and specialized training) if you have food allergy symptoms or another food-related condition.

At-home food allergy tests are an option, these tests can be purchased from pharmacies and online retailers and provide detailed instructions about how to perform the test safely and send it to a lab for evaluation. It is important to note that these tests may not be as sensitive as medical-grade testing, and the ACAAI recommends medical-grade testing if you are experiencing bothersome symptoms.

You can use Solv to locate nearby testing providers. Solv features a directory of all top-rated testing providers—including those that do allergy testing. You can also book an appointment directly from the Solv website.

What to expect during food allergy testing

During food allergy testing, you can expect the allergist to start by asking you questions about your symptoms to establish a history or allergic reaction to food. The allergist will ask questions about the food that you or your child eat, the characteristics of your symptoms, frequency, and how long it takes for you to develop symptoms after eating.

According to the National Library of Medicine (NLM), these are some of the questions you may need to answer before the test:

• Did you or your child eat eggs, peanuts, tree nuts, cow’s milk, shellfish, wheat, soy, or tinned fish two hours before your symptoms started?
• Did you or your child eat the food before?
• Did you or your child experience a reaction when you ate the food in the past?
• At what age or when did the allergic reactions to the food start?
• How was the food prepared? Did it have large or small amounts of the suspected food allergen?
• What symptoms did you or your child experience during the reaction?

The answers to these questions will help identify the type of food allergy and provide details about the type of allergic reaction involved. Once the allergist identifies the suspect food allergen, they can conduct a skin prick test, blood test, or both to confirm the diagnosis. If the results of these tests are inconclusive, the allergist may need to do an oral food challenge (OFC) test.

How to prepare for a food allergy test

Preparing for a food allergy test can involve several steps, depending on the type of test that will be performed. Here are some general guidelines to follow, according to the ACAAI:

• Consult with your healthcare provider: Before undergoing any type of allergy test, it is important to talk to your healthcare provider. They can help you understand the risks and benefits of the test, as well as what to expect during and after the procedure.
• Review your medications: Certain medications can interfere with allergy test results, so it is important to let your healthcare provider know about any medications you are currently taking. According to the ACAAI, antihistamines should be avoided for up to seven days before skin testing, as they can interfere with the skin's reaction to allergens. Other medications, such as corticosteroids and tricyclic antidepressants, can also affect test results.
• Avoid allergenic foods: If you suspect that you have a food allergy, you should avoid the allergenic food(s) for at least two weeks prior to the test. This will help to ensure that your body is not actively reacting to the allergen, which can lead to false negative results. However, it is important to consult with your healthcare provider before making any changes to your diet.
• Stay hydrated: Adequate hydration can help to prevent fainting or dizziness during blood testing. The ACAAI recommends drinking plenty of fluids before and after the test.
• Dress appropriately: If you will be undergoing a skin prick test, it is important to wear clothing that will allow easy access to your forearms, as this is where the test is usually performed.

Risks of food allergy testing

There is some inherent risk associated with food allergy testing, according to the NLM. During the OFC and skin prick test, an allergen will be introduced into your body—creating a risk of having a severe reaction to the test. You may also develop minor skin irritation, pain, or a minor bleed from the skin test or blood draw. The sight of blood may cause you or your child to faint.

Understanding your food allergy test results

Results from skin allergy tests are usually available within 15 to 20 minutes, according to the ACAAI. Your provider can discuss your results during your appointment. Results from blood allergy tests are usually available after several days, as it requires your provider to send your sample to the lab for evaluation.

Can I get an at-home food allergy test?

There are some at-home allergy testing kits available for purchase, however, at-home tests may not be as sensitive as medical-grade tests. It is best to see a medical provider if you suspect a food allergy, according to the ACAAI.

Cost of food allergy testing

The cost of food allergy testing in the USA can vary widely depending on the type of test, the location, the provider, and insurance coverage. Average costs, according to the Healthcare Bluebook, a website that provides estimates of fair prices for healthcare services, the price range for food allergy testing ranges from a couple of hundred dollars to several thousand dollars.

What foods commonly cause an allergic reaction?

There are many foods that can cause allergic reactions, but some are more common than others. Here are the top eight foods that account for the majority of food allergies, according to the ACAAI:

• Cow's milk
• Eggs
• Peanuts
• Tree nuts (such as almonds, cashews, and walnuts)
• Fish
• Shellfish (such as shrimp, crab, and lobster)
• Soy
• Wheat

It is important to note that food allergies can develop to any food, and some people may be allergic to foods that are not on this list. In addition, some people may be allergic to more than one type of food.