August 12, 2025

Carbon Footprint of Laboratory Testing in an Intensive Care Unit: Baseline Evaluation for a Quality Improvement Project

Key Points

The study quantified carbon emissions from laboratory investigations, revealing an average of 1.07 kgCO2e per patient-day in the ICU.
Over 1464 patient-days, notable carbon contributions were from routine tests like urea and liver panels, prompting reconsideration of practices.
Retrospective evaluation utilized Life Cycle Assessment data to analyze the environmental impact of these investigations.
The findings suggest targeted reduction strategies in laboratory testing to promote environmental sustainability in clinical practice.

Abstract

ABSTRACT Background Healthcare contributes 4%–5% to global carbon emissions. The intensive care unit (ICU) produces three times more carbon emissions per patient‐day than that of the general ward. Over‐ordering of laboratory investigations contributes to the carbon footprint in the ICU. Aim To evaluate the carbon footprint arising from laboratory investigations in the ICU over an 8‐month period. Study Design We conducted a retrospective single‐centre clinical practice baseline evaluation within a Sustainability in Quality Improvement (SusQI) project in the Surgical ICU in Singapore General Hospital. The number and types of laboratory investigations ordered for all patients admitted from May to December 2023 were extracted from the electronic medical records system. Existing process‐based Life Cycle Assessment (LCA) data were used to determine the carbon footprint of the investigations ordered. Results In total, 285 patients were admitted to the ICU, amounting to 1464 patient‐days. An average of 12.3 investigations were ordered per patient‐day. The total carbon emissions over this period were 1560 kg carbon dioxide equivalent (kgCO 2 e) or an average of 1.07 kgCO 2 e per patient‐day. The most common investigation ordered was urea, electrolytes and creatinine (UECr), while the liver panel ± gamma‐glutamyl transpeptidase (LFT ± GGT) generated the highest total carbon emissions (337.7 kgCO 2 e). A total of 20.7% of investigations lacked available LCA data. Conclusion Our study quantified the carbon footprint contributed by laboratory investigations in ICU from available LCA data. Although laboratory investigations contribute a small proportion of the total carbon footprint in the ICU, it is an area that can be targeted to reduce unnecessary carbon footprint as part of a holistic approach to environmental sustainability. Relevance to Clinical Practice This study highlights the environmental impact of laboratory investigations. Clinicians should be aware of this fact and avoid unnecessary laboratory investigations.

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