Key PointsQuestionCan an informatics tool improve detection of antibiotic allergic-type events?FindingsIn this cohort study of 36 344 patients who underwent cardiovascular implantable electronic device procedures, an electronic algorithm with high positive predictive value was developed that can be used to measure the occurrence of periprocedural antibiotic allergic-type events in near real-time. Most antibiotic allergic-type reactions were moderate in severity.MeaningThe algorithm developed in this study could be used to detect when antibiotic allergic-type reactions occur to provide direct clinician feedback about harms.