xRead - September 2022

Wise et al.

Page 75

defining the allergen responsible for LAR in patients who have had false-negative results with first-line tests and a high suspicion for clinically-relevant allergy. 308,318

Author Manuscript Author Manuscript Author Manuscript Author Manuscript

Basophil reactivity (% CD63+ cells determined at 1 allergen concentration) does not reflect the effect of allergen immunotherapy. There is good evidence to suggest that basophil sensitivity (EC50, or eliciting concentration at which 50% of basophils respond; also named CD-sens if it is inverted and multiplied by 100) is a marker for treatment effect of AIT 969-971,975-977 and anti-IgE treatment. 975 In summary, BAT may be a useful ex vivo test when diagnosis of AR is in doubt or the allergen responsible for clinical symptoms is unknown. Basophil sensitivity is also useful for measuring response to AIT. When the methodology of BAT is more clearly standardized, it may become a more useful second line test in AR diagnosis, as using an ex vivo test is beneficial in terms of time taken to undergo testing and symptoms evoked during testing. Most studies included small samples sizes with less than 100 patients. There is an opportunity for a meta-analysis of these studies or a larger scale trial to confirm the findings of the works included in this review. • Aggregate Grade of Evidence: B (Level 1b: 2 studies; Level 2b: 2 studies; Level 3b: 8 studies; Level 4: 3 studies; Table VIII.F.5). • Benefit: Ex vivo test, patient discomfort minimal, less time consuming than nasal provocation and SPT for patient, reliable correlation between clinical symptoms and basophil sensitivity when measuring response to therapy, no risk of anaphylaxis compared to provocation testing. • Harm: None known. • Cost: Requires proximity of laboratory trained in basophil testing. Cost of testing. • Benefits-Harm Assessment: Balance of benefit over harm. • Value Judgments: Basophil sensitivity may be a useful marker for following response to immunotherapy. Differences in BAT methodology for diagnosis of AR and rare need for laboratory tests to diagnose AR make it likely to be implemented for diagnosis in tertiary care centers only. • Policy Level: Option. • Intervention: BAT is an option for AR diagnosis when first-line tests are inconclusive or for measuring response to AIT. Many small-scale studies have been completed. There is scope for meta-analysis and for larger trials to be completed. VIII.F.6. Component resolved diagnosis (CRD)— Molecular diagnosis (MD) or component resolved diagnosis (CRD) is used in allergy to define the allergen sensitization of a patient at the individual protein level by measuring sIgE to purified natural or recombinant allergens, allowing identification of the potential disease-eliciting molecules. Overall, MD can potentially improve diagnostic accuracy (specificity), distinguish cross-reactivity

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