As early peanut introduction becomes more common, component testing is playing a larger role in distinguishing allergy from sensitization.
By Alyx Arnett
A decade ago, parents of infants thought to be at risk for peanut allergy were often advised to delay peanut exposure. Today, research points in the opposite direction, with multiple studies showing that earlier introduction can reduce the likelihood of developing a peanut allergy. A new study published in Pediatrics adds to that evidence, reinforcing findings from earlier trials that linked early peanut introduction with lower allergy risk.
As guidance has shifted, so has the need for clearer answers at the point of care—particularly when clinicians and families are weighing whether early peanut introduction is appropriate for an individual infant. Gary Falcetano, PA, senior manager of global medical and scientific affairs, allergy, at Thermo Fisher Scientific, says laboratory testing plays an increasingly important role in helping clinicians assess allergy risk before moving forward.
Advances in peanut component testing now allow laboratories to move beyond a simple positive-or-negative result. By identifying which specific peanut proteins a patient is sensitized to and pairing that information with clinical history, providers can better assess risk, avoid unnecessary dietary restrictions, and reduce reliance on higher-risk oral food challenges.
In this Q&A, Falcetano discusses how peanut component testing has evolved, how laboratories support early introduction strategies, and what recent prevention-focused research could mean for the future of allergy diagnostics.
CLP: How has peanut component testing evolved over the past decade, and what impact has it had on diagnosing peanut allergy versus sensitization?
Falcetano: The evolution of peanut component testing has moved from exclusively traditional methods to include the addition of more precise molecular testing, starting with skin prick tests (SPT) and whole allergen specific IgE tests, progressing to include more individual-allergen component analysis in the past decade, like the US Food and Drug Administration’s 2018 approval of Thermo Fisher Scientific’s Ara h 6 component test. Ara h 6, along with Ara h 1, 2, and 3, are usually associated with a higher risk for systemic reactions or anaphylaxis, underscoring the availability of this test as an important step forward in peanut allergen component testing.
With more specificity, clinicians can now determine which proteins patients are sensitized towards. With a comprehensive understanding of patient symptom history, they’re able to determine more accurately when a patient is merely sensitized versus when they’re likely to have a systemic reaction upon exposure. Whole allergen and allergen component testing coupled with a comprehensive symptom history can help clinicians provide more precise, personalized treatment recommendations and potentially reduce the need for higher-risk oral food challenges.
CLP: Which peanut components are most clinically relevant for predicting reaction severity, and how are laboratories ensuring accurate detection?
Falcetano: Among peanut proteins, patients with elevated IgE to Ara h 1, 2, 3, and 6 are all usually associated with a higher risk for systemic reactions. Sensitization to other components like Ara h 8, CCD, and Bet v 2, which are denatured by heat and digestion, as opposed to Ara 1, 2, and 3, may indicate that patients will have either no clinical symptoms or isolated oral symptoms. This is known as Pollen Food Allergy Syndrome (PFAS), a common condition caused by the immune system’s reaction to similar proteins, or components, found in foods and pollens.
Laboratories help ensure accurate detection by testing with standardized, highly sensitive assays. This level of sensitivity and specificity enables clinicians to distinguish clinical allergies from mere sensitization, guide oral food challenges safely, and make evidence-based recommendations for early peanut introduction or avoidance.
CLP: The Pediatrics study highlights early peanut introduction as a prevention strategy. How do laboratory diagnostics support clinicians in determining which infants are candidates for early introduction?
Falcetano: The Pediatrics study was a real-world, United States-based validation of what we have known since the original “Leap Trial” was published in 2015. Both studies demonstrated significant reductions in the incidence of peanut allergy among children who had early introduction of peanuts into their diets during the first year of life.
When clinicians and parents have reason to suspect a peanut allergy and are reluctant to recommend or incorporate early introduction of peanut into a child’s diet, laboratories can support diagnostic decision making by offering high-quality whole allergen and allergen component testing to aid in the diagnosis of suspected peanut allergy. In fact, a recent study confirmed the clinical utility of peanut components for the diagnosis of peanut allergy in infants.
CLP: How do labs balance specificity and sensitivity in component testing to minimize both false positives and unnecessary dietary restrictions?
Falcetano: Assessment of potential allergic disorders begins with a clear understanding of clinical allergy versus sensitization to an allergen. Specific IgE testing with whole extract ImmunoCAP assays has a high level of sensitivity, meaning that obtaining a negative result to a suspected allergen indicates that it’s most likely not the cause of the symptoms that prompted the testing. Generally, the addition of specific IgE allergen component testing adds specificity and increases the positive predictive value that helps confirm a positive result is both clinically relevant and may indeed be the cause of the symptoms.
Allergen component tests help pinpoint the specific proteins responsible for triggering symptoms, which not only adds specificity to the diagnosis but also helps identify irrelevant cross-reactivity. Detailed results from these tests show the levels of allergen-specific IgE antibodies in blood and can reveal sensitization from among a selection of hundreds of possible allergens and allergen components. Basing test selection on a detailed patient history allows clinicians to have a much better understanding of how a particular patient may express their disease and informs a more precise diagnosis.
For a patient to have a clinical food allergy, they must have also symptoms upon exposure to food. Because of this, taking the right diagnostic approach, which includes gathering a comprehensive patient history, is critical. This helps ensure that patients who are only sensitized, but not clinically allergic, are not placed on unnecessary dietary restrictions. Improving diagnostic specificity also means that clinicians may be able to perform fewer higher-risk oral food challenges and potentially more lower-risk food challenges to get patients to an accurate diagnosis.
CLP: What role does standardization play in ensuring consistent peanut allergy testing results across laboratories?
Falcetano: Consistent calibration, assay harmonization, and adherence to validated testing protocols all help ensure that test results are accurate and can help a clinician determine if a patient has a clinical allergy, regardless of the allergen(s) they’re testing for.
A lack of standardization could cause differences in assay performance and interpretation of results, which may lead to inconsistent or incorrect diagnoses, undiagnosed clinical allergies, or, as mentioned, unnecessary oral food challenges that limit the patient’s diet. Standardization also enables laboratories to provide clinicians with results they trust to make informed, precise diagnostic and treatment decisions for their patients.
CLP: Are there new or emerging technologies advancing peanut or other food allergy diagnostics?
Falcetano: While not necessarily “new,” allergy diagnostics are increasingly focused on component-resolved testing. This kind of testing looks at specific proteins within an allergen as opposed to whole allergen testing, which determines if there’s a sensitization to an allergen but doesn’t provide insight into which specific protein may be causing a reaction.
For peanut allergies, testing for individual components helps provide insight into potential allergic sensitization to each protein. For example, Ara h 6 is a storage protein closely related to Ara h 2 that’s associated with a higher risk for severe allergic reactions. Identifying sensitization to Ara h 6 alongside other major peanut allergens can help clinicians more accurately assess risk and anticipate the potential severity of reactions.
Component testing also helps determine if there is cross-reactivity with other allergens, such as pollens. For peanuts specifically, common pollen allergies that could cause PFAS when eating peanuts include tree (eg, birch), grass, and weed.
Ultimately, understanding which protein the patient has a clinical allergy to helps them understand their allergy better and enables them and their care team to develop a more precise and informed treatment plan.
CLP: Looking ahead, how might recent findings in peanut allergy prevention influence the broader approach to allergy diagnostics and patient management in the lab setting?
Falcetano: We will continue to see diagnostics in general, and allergy diagnostics in particular, continue to be utilized to allow more precise diagnosis and more personalized approaches in our management of patients. It is essential for laboratories to offer the highest-quality assays from trusted partners to empower clinicians to have the best tools and decision support for the care of patients with suspected allergic diseases.
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