Peanut Allergy and the Basophil Activation Test in the Military Healthcare System: A Case Series of Monozygotic Twins.

Based on current standards for accession into the U.S. military, food allergy represents a significant barrier to military service. Skin prick and serum specific IgE testing exhibit high sensitivity but low positive predictive value, often leading to overdiagnosis when a confirmatory oral food challenge (OFC) is subsequently avoided because of concern for anaphylaxis in the clinic. Basophil activation testing (BAT) offers a unique advantage by measuring in vitro basophil responses to peanut allergen and can provide superior risk stratification for safe OFCs. We report the first clinical application of BAT for peanut allergy delabeling in monozygotic twins. Both adolescent twin military dependents carried longstanding peanut allergy labels based on positive routine allergy testing. BAT demonstrated low basophil activation levels with exposure to peanut allergen, indicating a low risk of reaction from OFC. Both twins successfully completed full-dose supervised peanut challenges without IgE-mediated reactions, leading to removal of their food allergy label and eliminating dietary restrictions. This case demonstrates military medicine's leadership in implementing innovative diagnostics. Walter Reed is the first known military treatment facility to offer clinical BAT, positioning the Military Health System to contribute valuable data supporting future standardization and regulatory approval. BAT implementation as a sequential risk-stratification tool represents an advancement in evidence-based allergy evaluation, safely removing unnecessary barriers to military service while maintaining rigorous patient safety standards.