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Wise et al.

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allergens in LAR may permit allergen avoidance and immunotherapy. 107 AIT is the treatment of choice for patients with AR who have failed allergen avoidance and medical therapy. Patients who are classified as NAR, would not typically be candidates for AIT. However, as previously noted, roughly 50% of patients with negative systemic testing have been shown to have LAR. In this LAR population, early studies suggest that AIT can decrease symptoms and medication usage, and improve QOL. 288,957 • Aggregate Grade of Evidence: C (Level 2b: 13 studies; Level 3b: 3 studies; Level 4: 8 studies; Table VIII.F.4). • Benefit: Identifying patients with LAR allows for the opportunity to treat a subset of patients who may respond to avoidance or AIT. Identification of nasal sIgE allows for diagnosis and AIT. • Harm: Measurement of nasal sIgE is minimally invasive, and no adverse effects have been reported. • Cost: Associated costs consist of the direct costs of testing, and indirect cost of increased time and effort for performing nasal sIgE diagnostic test. • Benefits-Harm Assessment: The benefits of identifying patients with an allergic component to their rhinitis may outweigh any associated risks. • Value Judgments: In patients with rhinitic symptoms and negative systemic testing, identifying nasal sIgE may assist with appropriate treatment. Standards for abnormal levels of nasal sIgE have not been established nor correlated with clinical outcomes. • Policy Level: Option. • Intervention: Nasal sIgE levels is an option in patients with suspected or known LAR to aid in diagnosis or guide allergen-specific therapy. VIII.F.5. Basophil activation test (BAT)— The basophil activation test (BAT) is an ex vivo peripheral blood test that has been shown to be useful in the diagnosis of allergy to food and drugs, along with other hypersensitivity syndromes, when first-line tests (SPT and serum sIgE) are discordant with clinical history or do not exist, and for monitoring of AIT. 966 Within the field of AR, there are small-scale trials evaluating the utility and reliability of BAT in testing for the diagnosis of specific allergens related to AR symptoms and monitoring therapy (Table VIII.F.5). BAT methodology was found to be heterogeneous between trials. Most data pertaining to its accuracy used the tetraspanin CD63 (lysosome-associated membrane glycoprotein 3 [LAMP 3]) as an activation marker. 967-971 CD203c (ecto-nucleotide pyrophosphatase/ phosphodiesterase 3) is less frequently used. 968,972 In 1 trial, it held potential as a sensitive and specific method of testing for AR as compared to CD63. 968 The diagnosis of AR is a clinical decision guided by skin or serological tests; ex vivo basophil testing is rarely required. However, BAT has been shown to be comparable with traditional allergen testing methods. 967,970,973,974 BAT has been shown to be useful in

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Int Forum Allergy Rhinol . Author manuscript; available in PMC 2020 June 10.