How Does Food Allergy Testing Work?

How Does Food Allergy Testing Work?

Millions of Americans have at least one food allergy. While unknown allergies can be life-threatening, they become manageable with the right medical guidance. The first step to effective allergy management is diagnosis. Bergen Medical Associates is a medical practice in New Jersey with over 40 board-certified practitioners, including allergists. Here, our allergy and immunology team discusses why food allergy testing is important and the different methods used to identify an allergy.

Why Is Food Allergy Testing Important?

Many patients may be tempted to avoid food allergy testing. It seems like unnecessary discomfort to confirm something that should be obvious. Even when a reaction seems clear-cut, however, it is still important to seek food allergy testing.

Food allergies can resemble food intolerances, especially when they cause digestive symptoms. The two issues, however, are not the same. Allergies are an immune response caused by the patient’s body overreacting to a foreign body. Food intolerances, meanwhile, are an inability to fully break down certain food types. Food allergy testing can help the patient understand which type of issue they have, which is important for effective management.

Allergy testing also provides useful information about cross-reactivity. When a person is allergic to one food, they are also likely to react to other similar foods. For example, if the patient has a reaction to walnuts, they may have similar issues with other nuts. Food allergy testing is used to predict cross-reactivity, helping patients avoid unexpected issues.

When Should Someone Get Food Allergy Testing?

There are many reasons to pursue food allergy testing. Though most patients get testing after having a reaction, this is not the only motivation to speak with a medical practitioner about possible allergies. These are just a few signs that allergy testing is a good idea:

• The person has experienced a suspected allergic reaction
• The patient has close family members with known allergies
• The patient has a childhood allergy that they might have outgrown
• The patient has a known allergy and wishes to know about cross-reactivities
• The patient wishes to know what allergies they may pass down to a child

Food allergy testing can provide answers to all the above questions and more. It can also connect the patient with a board-certified nutritionist who can provide advice for avoiding allergy triggers, helping patients follow a diet that is healthy, delicious, and allergy-free.

Are There Different Types of Food Allergy Testing?

There is no single method for diagnosing food allergies. Instead, allergists use a variety of test types to form as complete a picture of the patient’s condition as possible. Most food allergy testing progresses through multiple stages to rule out possibilities and eliminate false positives, though not every patient will go through every stage. These include:

Medical History Evaluation

Food allergy testing typically begins with a review of the patient’s medical history. The allergist asks questions about the patient’s allergic reaction and its triggers. Patients can help by taking notes on their experience. They should be prepared to provide the following information:

• What type of food did the patient eat?
• How much of it was consumed?
• How long did it take for a reaction to occur?
• What symptoms did the patient experience?
• How long did symptoms last?
• Does the reaction occur with other foods?

The allergist may also ask questions about the patient’s family. While not all food allergies are genetic, many of them are. If a patient’s parent, sibling, child, or other family member has a known food allergy, then the patient is more likely to develop the same or a similar allergy.

Blood Tests

To perform an allergy blood test, a phlebotomist takes a small sample of blood. The sample is sent to a medical lab to be tested for antibodies. These are specialized proteins produced by the immune system to fight infections. Each type of antibody has a unique shape to latch onto a specific type of invader, like a key that only fits one lock. By measuring the amounts of each type of antibody, physicians can predict an immune response, such as an allergy.

Blood tests typically take a few days to a week to produce results. They are slightly less exact than other tests. They can be used to test many different allergies at once, however, making them an effective way to narrow down the possibilities.

Skin Prick Tests

Skin prick tests are the most common method for diagnosing food allergies. During this test, the allergist places liquid on the patient’s arm or back. The liquid contains tiny amounts of the suspected food allergen. The allergist then pricks the skin under the liquid, allowing it to seep under the skin. The test is positive if a weal, or a tiny bump like a mosquito bite, forms at the prick site. This is not painful, though it may be itchy or uncomfortable.

Skin prick tests return results within 20 minutes and are often used to confirm the results of a previous blood test. They are one of the most accurate food allergy test types available, though they can still return false positives.

Oral Food Challenge

Oral food challenges are considered the gold standard of food allergy testing. During this test, the patient is fed small amounts of the suspected trigger food with increasing doses over a period. The patient is then observed for several hours in the hospital. Medical support is readily available in case the patient experiences a reaction.

Oral food challenges are the most accurate method for diagnosing food allergies and can be helpful if blood or skin prick tests are inconclusive. Due to the risk of anaphylaxis, however, this test is not always recommended. It is performed only when deemed necessary, and always by a board-certified allergist with emergency equipment and medication on hand.

Find Comprehensive Food Allergy Testing Near You in New Jersey

Though unexpected allergic reactions can be startling, testing and diagnosis give patients the tools they need to manage allergies effectively. Bergen Medical Associates offers food allergy testing at convenient locations near you in northern New Jersey, helping patients avoid severe reactions. To learn more about testing or to get started, request an appointment today. We have locations in Emerson, Montvale, Northvale, Paramus, and Ridgewood, NJ, making it easy to find treatment near you.