Background Diagnostic testing has been proposed as a key strategy to tackle escalating antimicrobial resistance (AMR). However, effectiveness of testing is limited by the complexities of the hospital environment, including human factors.

Objectives To examine swab-testing in diabetes-related foot infections as a case study of the factors impacting microbiology testing use, efficacy, and antimicrobial resistance.

Methods Seventeen clinicians involved in the management of diabetes-related foot infections, including podiatrists, nurses, and doctors, participated in in-depth individual interviews conducted by a qualitative researcher on the investigation and management of diabetes-related foot infections. Thematic analysis was performed.

Results The multilayered and evolving features of the human-diagnostic interface were described by participants as potential barriers to effective swab-testing in clinical care, including diagnostic training and interpretation deficits; communication difficulties; interpretation deficits and diagnostic assumptions; the influence of inter-professional dynamics; and flow-on consequences for patient decisions and care.

Conclusions Swab-testing has been used for over 100 years, and yet there remain substantial factors that limit their effective use in clinical practice as demonstrated by this study. A focus on upscaling diagnostic testing, particularly with escalating AMR, without considering complex implementation and human factors is likely to have limited impact on practice improvement. This study identified vulnerability points in the human-diagnostic interaction which should be considered in the implementation of other microbiological tests. This study on the simple wound swab has implications for future diagnostic upscaling and investment, including its role in address antimicrobial resistance.