Point-of-Care β-Lactam Allergy Skin Testing by Antimicrobial Stewardship Programs: A Pragmatic Multicenter Prospective Evaluation.

Background: β-lactam allergy skin testing (BLAST) is recommended by antimicrobial stewardship program (ASP) guidelines, yet few studies have systematically evaluated its impact when delivered at point of care.
Methods: We conducted a pragmatic multicenter prospective evaluation of the use of point-of-care BLAST by ASPs. In staggered 3-month intervals, ASP teams at 3 hospitals received training by allergists to offer BLAST for eligible patients with infectious diseases receiving nonpreferred therapy due to severity of their reported allergy. The primary outcome was the proportion of patients receiving the preferred β-lactam therapy.
Results: Of 827 patients with reported β-lactam allergy over 15 months, β-lactam therapy was preferred among 632 (76%). During baseline periods, 50% (124/246) received preferred β-lactam therapy based on history, compared with 60% (232/386) during the intervention periods (P = .02), which improved further to 81% (313/386) upon provision of BLAST (P < .001) without any increase in incidence of adverse drug reactions (4% vs 3%; P = .4). After adjusting for patient variables and the correlation between hospitals, the intervention period was associated with a 4.5-fold greater odds of receiving preferred β-lactam therapy (95% confidence interval, 2.4-8.2; P < .0001). Conclusions: The use of BLAST at the point of care across 3 hospital ASPs resulted in greater use of preferred β-lactam therapy without increasing the risk of adverse drug reactions. Longer-term studies are needed to better assess the safety and clinical impact of this ASP intervention.