Assessing the carbon footprint of medical diagnostic testing: a scoping review protocol

The climate crisis represents an unprecedented threat to global health systems, requiring urgent decarbonisation across all healthcare sectors. Although medical diagnostics affect approximately 70% of clinical decisions, they receive disproportionately little attention in healthcare sustainability research. This knowledge gap is particularly concerning as the impact of climate change on health may increase diagnostic testing demands, potentially creating a feedback loop of environmental harm. Carbon assessment methodologies within healthcare are heterogeneous and context-specific, with varying methodologies and assumptions complicating systematic evaluation. The proposed scoping review aims to map and analyse the existing literature on medical diagnostic carbon footprints, synthesising methodological approaches, core assumptions and evidence gaps to guide future decarbonisation efforts.

Four electronic databases (PubMed, Embase, Web of Science and HealthcareLCA) will be systematically searched from their inception to January 2025. The search strategy will combine subject headings and text words related to (1) carbon footprint and (2) diagnostic testing of any form. Only published, peer-reviewed studies will be considered, with no exclusions made on the basis of language, location or publication date. Two independent reviewers will screen titles/abstracts and full texts, with disagreements resolved through discussion. Data will be extracted using a bespoke tool developed and piloted by the research team to capture study characteristics, methodological approaches and key findings. Narrative synthesis and descriptive quantitative analysis will be used to analyse the data. The review will be reported in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews checklist.

Ethical approval is not required for this scoping review. Our findings will be published in a peer-reviewed scientific journal and presented at scientific conferences.