The implementation of electronic clinical decision tools to reduce inappropriate urine & swab requests: a diagnostic stewardship intervention to reduce the environmental impact of laboratory testing

The NHS accounts for approximately 4-5% of England's total carbon footprint and was the first healthcare organisation to commit to a net-zero target. Reducing the inappropriate use of diagnostic tests could play a meaningful role in reaching this goal. In 2024, the microbiology laboratory at Lancashire Teaching Hospitals NHS Foundation Trust received >90,000 urine and >15,000 wound samples. Local audit data highlights samples are sent for testing in the absence of clinical signs and symptoms of infection. Furthermore, 25 % of superficial swabs and 10% of urines grew mixed-faecal organisms. The aim was to implement a diagnostic stewardship intervention to reduce inappropriate urine and wound swab submissions from primary care and estimate associated carbon savings. A pre-analytical stage diagnostic stewardship intervention was implemented consisting of a computerised clinical decision support tool (CCDS). The tool prompts clinicians, using evidence-based guidance, on when to obtain samples for testing. The UK Government 2024 greenhouse gas conversion factors were used to calculate the total CO2e associated with testing urine and wound samples. 3-month intervention period data was compared with two 3-month pre-intervention periods (I and II). Comparing number of samples received during the intervention period with pre-intervention II, urine samples decreased by 10.2%, saving 190.5kg CO₂e. Similarly, wound samples decreased by 12.9%, saving 80kg CO₂e. The CCDS tool effectively reduced unnecessary testing and associated carbon emissions, supporting the NHS's net-zero ambitions. Similar tools can be employed in other areas of pathology to reduce the impact of inappropriate testing whilst supporting sustainable healthcare.