A comparison of the carbon footprint of alternative sampling approaches for cervical screening in the UK: A descriptive study

Objective: To understand whether self-sampling can reduce carbon emissions (CO2 e) from the NHS cervical screening programme (NHSCSP) by comparing the carbon footprint of three sampling strategies: routine cervical sampling, vaginal self-sampling and first-void (FV) urine collection.Design: Descriptive study.Setting: National Health Service (NHS), United Kingdom (UK).Population or sample: Patients aged 25-64 years eligible for cervical screening in the UK.Methods: A carbon footprint analysis was undertaken for three cervical screening sampling approaches, from point of invitation to screening through to preparation for transport to the laboratory for HPV testing. A combination of primary and secondary data were used, with a bottom-up approach applied to collection of primary data.Main outcome measures: We report CO2 e per sampling approach, which is the unit used to express carbon footprint and harmonise the contributions of greenhouse gases with different global warming potentials.Results: The total carbon footprint of routine cervical sampling is 3670 g CO2 e. By comparison, vaginal self-sampling had a total carbon footprint of 423 g CO2 e, and FV urine sampling 570 g CO2 e. The largest share of emissions for routine sampling was attributable to the carbon footprint associated with an appointment in a primary care setting, which totalled 2768 g CO2 e.Conclusions: Routine cervical sampling is up to 8.7-fold more carbon-intensive than self-sampling approaches with equivalent effectiveness. We found negligible differences in the carbon footprint of alternative self-sampling methods, supporting the need for an informed choice of screening options for participants, which includes sharing information on their environmental impacts.Keywords: carbon footprint; cervical screening; screening uptake; self-sampling; sustainab