Barriers and enablers to penicillin allergy assessment and testing in the intensive care unit: A mixed-methods study

Penicillin allergy (PenA) labels are common and often do not represent true immune-mediated allergy, yet are not routinely assessed or tested in the ICU. With greater demand for effective antimicrobial stewardship, and growing support for non-allergist performed PenA assessment, enthusiasm for routine ICU-led PenA evaluation is increasing. However, we do not presently understand key factors needed to plan and deliver such a change.

We conducted a convergent mixed-methods study combining an electronic survey of ICU healthcare staff with follow-up interviews. Participants included those working in ICUs with and without PenA assessment programmes. Survey data were analysed descriptively. Interview and free-text data underwent thematic analysis guided by the Theoretical Domains Framework (TDF). Quantitative and qualitative findings were integrated at the interpretation stage.

Overall, 113 healthcare staff completed the survey and 13 participated in interviews. Barriers to implementation included limited training, poor guideline awareness, low confidence in risk stratification and drug challenge procedures, perceived medico-legal risk, unclear ownership, and workload pressures. Enablers included clear governance structures, robust protocols, decision support tools, access to specialist advice, local champions, and audit and feedback mechanisms. Participants working in ICUs with established programmes described greater confidence and integration of PenA assessment into routine practice.

Variation in ICU-led PenA assessment appears to reflect organisational and behavioural influences rather than intrinsic clinical barriers. Differences between settings were associated with governance structures, leadership, education, and social reinforcement. Addressing these determinants may support more consistent integration of PenA assessment into routine ICU practice.