PHOENIX — For at least a decade, professional allergy and pediatrics societies have urged against using food IgE tests without a history consistent with potential IgE-mediated food allergies. Yet virtually every health system offers these blood tests, and their inappropriate use — especially of panels that measure many allergens at once — remains a huge problem.
Beyond wasteful spending, excessive food IgE testing can lead patients to worry needlessly and to avoid foods they aren't allergic to. For babies and toddlers, avoidance can drive up the risk of developing allergies to those foods later in life — a consequence that was convincingly proven by the LEAP study but has still not translated to a widespread change in practice
"I think we all know that there's just a lot of system-wide resistance to making these changes, and we don't completely understand why," Nicholas Hartog, MD, an allergist with Spectrum Health in Grand Rapids, Michigan, told Medscape Medical News.
At the American Academy of Allergy, Asthma, & Immunology (AAAAI) 2022 Annual Meeting last weekend, one of Hartog's residents, Courtney Cotter, DO, presented a poster detailing their team's retrospective review of food panel ordering practices across Spectrum Health, a large, multispecialty physician group in west Michigan.
The team combed Epic health records to evaluate food IgE ordering from January 2016 to December 2021. They tracked monthly figures for the number of patients who underwent food IgE tests, the percentage of tested patients for whom food panels were available, and the number of food panels and total number of food IgE tests ordered. They compared average rates from the final 3 months with rates from the first 3 months, which predated the August 2016 establishment of an academic pediatric allergy/immunology department.
Initially, Hartog and his colleagues focused on educating doctors on appropriate use of food IgE tests through informal conversations and lectures, but, he said, "It's really difficult to change physician behavior, so sometimes we have to go about it by making it hard to do the wrong thing."
To that end, the team tried to eliminate the food panels. However, some lab staff feared the possibility of losing revenue if physicians decided to order these tests elsewhere. After more negotiations, the laboratory agreed in December 2019 to restrict and rework food IgE testing by dropping the number of panels from nine to two and by restricting the number of foods in those panels. For example, in the basic panel, "we limited it to just four allergens, so even if you order a panel, you're not getting 20 results," Hartog told Medscape Medical News. "I finally found a friendly pathologist who was very on board with this positive change."
In December 2020, the team implemented yet another strategy: Epic alerts. Each time doctors request a food panel, they receive a pop-up message stating that panel tests are not recommended and asking if they wish to proceed.
The multipronged effort had a modest impact on the number of food panels ordered per month, which dipped from 112.7 to 84.7 for the first and last 3 months of the study. Monthly totals of individual food IgE tests showed a steeper drop, decreasing from 2379 to 1180 in the initial and final 3-month periods — a change Hartog attributes to the revamped food panels. They estimated the cost savings at around $40 per patient, "and we were getting on average about 200 patients a month, so it adds up," he said.
But the Epic alerts seemed to have little effect. Over the duration of the study, the monthly number of IgE tests ordered per clinician did not change. Neither did the percentage of patients evaluated with a food panel. "The alerts pop up, but people are still ordering," Hartog said.
On the whole, the analysis shows that "despite major efforts to educate providers and the public about these things, it is rampantly disregarded and is a huge problem for our specialty and is likely causing harm to patients," said allergist-immunologist Gerald Lee, MD, of Emory University School of Medicine in Atlanta, Georgia.
Lee said that a common scenario for inappropriate food IgE testing is severe eczema. Many parents request blood tests because they assume their child's skin condition is driven by food allergies. When the child turns up positive to various foods on panel tests, which have high false positive rates, the physician may recommend eliminating those foods to improve the skin rash — which "actually delays introduction of the food and potentially increases the risk for food allergy," Lee said. "That was a common practice when I was in fellowship (2011) and is widely prevalent today."
Edwin Kim, MD, director of the UNC Food Allergy Initiative at the University of North Carolina School of Medicine in Chapel Hill, agrees that food IgE panels are wasteful and harmful. However, he thinks the solution is not to tell primary care physicians and pediatricians to stop using the tests. "We're insinuating that they're being used inappropriately, but the problem is that these are people that are patient-facing, the patients are asking a question, and the appropriate tests aren't there," Kim said. "A big part of that problem is that the tests we have available to us are not good enough."
The Spectrum Health analysis did not examine ICD codes associated with the food IgE tests or track which physicians ordered the tests. A 2016 retrospective review published in Pediatrics did evaluate ordering practices by specialty and found that primary care providers ordered "significantly more food allergen panels, tests for uncommon causes of food allergy, and generate higher cost per patient compared with allergists."
Given the immense challenges with implementing system-wide changes, sometimes it can help to educate parents and families. "When you sit down and take 2 or 3 minutes to explain why this is a bad test and that I care about your kid but just don't want inappropriate testing, they're okay with it. They understand," Hartog said. "When I teach residents, I make sure to emphasize that we have these conversations all the time."
Nicholas Hartog reports financial relationships with Binding Site (speaker), Regeneron (advisory board), Genentech (advisory board), Horizon Pharmaceuticals (advisory board, consulting, speaker), Takeda (speaker, advisory board) and Pharming Healthcare (advisory board, scientific steering committee, consulting), though none related to food allergy. Gerald Lee has disclosed no relevant financial relationships. Edwin Kim reports consultancy with Aimmune Therapeutics, Allako, AllerGenis, Belhaven Pharma, DBV Technologies, Duke Clinical Research Institute, and Nutricia; advisory board membership with ALK, DBV Technologies, Kenota Health, and Ukko; and grant support from the NIH's National Institute of Allergy and Infectious Diseases, National Center for Complementary and Integrative Health and Immune Tolerance Network; Food Allergy Research and Education, and the Wallace Research Foundation.
American Academy of Allergy, Asthma, & Immunology (AAAAI) 2022 Annual Meeting: Poster 316. Presented February 27, 2022.
Esther Landhuis is a freelance science journalist in the San Francisco Bay Area. She can be found on Twitter @elandhuis.
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Image 1: Spectrum Health
Image 2: Emory University
Image 3: University of North Carolina
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Cite this: Esther Landhuis. Managing Overuse of Food IgE Panels: Multiple Approaches Needed - Medscape - Mar 04, 2022.