November 4, 2019Lakiea Wright, MD, MPH
New research suggests that in the US, one in 10 adults and one in 13 children have a food allergy. That’s some 32 million Americans overall, and according to FARE (Food Allergy Research and Education) every three minutes, a food allergy reaction sends someone to the emergency room.
Common foods are usually the culprit. In fact, the vast majority (90 percent) of food allergies are caused by what many of us would consider dietary staples: milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, or soybeans. The allergic reaction can occur within a few minutes or up to two hours after ingestion, and the symptoms associated with these reactions can vary wildly, from hives and a skin rash all the way to anaphylaxis.
Accurate diagnosis of a food allergy is critical—not only to prevent severe, life-threatening allergic reactions, but also to help patients maintain their quality of life and avoid unnecessary dietary restrictions. Historically, the standard diagnostic workup required a clinician to assess the patient’s reactions, gather a detailed patient history, and then recommend skin prick testing and/or in vitro blood testing for food-specific, whole allergen immunoglobulin E (IgE) levels.
IgE is the antibody produced in response to a food allergen, in allergic patients. The food-specific IgE binds and activates mast cells, which triggers food allergy symptoms, so its presence can help identify potential food allergies. But specific IgE results only paint part of the picture. Based on the specific IgE results, clinicians who are uncertain of the culprit food allergen might still recommend an oral food challenge to clarify the diagnosis.
Until recently, whole allergen testing followed by an oral food challenge was the only way for clinicians and patients to truly understand the severity of a suspected food allergy. But over the past few years, the development of allergen component testing has improved this traditional diagnostic approach. Allergen component testing can provide deeper insights into a patient’s food allergy by pinpointing the specific protein(s) that may be causing symptoms.
Allergen component testing offers multiple benefits
As its name implies, allergen component testing measures the level of IgE associated with the specific component proteins that are associated with risk of severe allergic reaction. Here’s why allergen component testing should be included in a lab’s diagnostic offerings:
- Allergen component testing fills a gap in diagnostic results. Allergen component testing is one more piece of the puzzle that can help clinicians determine if a patient has a life-threatening food allergy.
- Allergen component testing can improve patient—and lab—management. Offering allergen component testing at the same time as whole allergen testing or as a reflex test is a more efficient use of laboratory resources that can help patients avoid additional office visits and blood draws.
- Allergen component testing can help identify appropriate candidates for oral food challenge. Since allergen component testing focuses on proteins associated with a higher risk of systemic allergic reactions, the results can help clinicians decide whether or not someone should avoid a food altogether or proceed with an oral food challenge.
- Reimbursements for food allergy tests differ. Allergen component testing has a different procedural code and is reimbursed at a higher rate than whole allergen testing.
- There is a patient behind every blood test. While some patients may experience only mild symptoms, for others, a food allergy can be life-threatening. Allergen component testing can help gauge where a patient falls on that spectrum, potentially reducing anxiety and helping to determine which, if any, dietary restrictions are necessary.
Allergy component testing improves diagnosis of peanut allergy
Allergen component testing has been studied most extensively for the diagnosis of peanut allergy—and for good reason. While peanut allergic reactions are generally the most common culprit of fatal food-induced anaphylaxis, peanuts and peanut products are quite commonplace.
Diagnostic testing for peanut allergy typically starts with blood or skin testing for the whole allergen, i.e., all of the proteins found in a peanut. Once these tests produce a positive result showing that patient is sensitized to peanuts, the next questions become, “Is this patient at risk for a systemic reaction like anaphylaxis? Or can the patient actually tolerate peanuts, and therefore be a good candidate to proceed with an oral food challenge?”
Allergen component testing can help provide those answers.
While researching peanut allergy, scientists found that the peanut protein Ara h 6 can cause severe allergic reactions in certain individuals. So, adding an Ara h 6 test to the existing peanut component assays (Ara h 1, 2, 3, 8 and 9) enables labs to provide a more complete view of a patient’s overall peanut sensitization. The results of an Ara h 6 diagnostic test can help determine the likelihood of a future life-threatening systemic reaction and help clinicians make more informed decisions regarding their patients’ allergy management plans.
As allergen component testing evolves and expands to include other specific high-risk food proteins, it will help allergists and other medical providers better predict which patients may be at risk for life-threatening reactions to certain foods. Getting this specificity of information from one blood draw can significantly improve the patient experience, while saving lab time and resources.