Diagnostic waste constitutes a tenth of all medical waste1, and most is infectious or hazardous, making reuse and recycling challenging. This includes waste generated from single-use diagnostic tests, laboratory reagents, and other related materials. The rising adoption of point-of-care diagnostic tests will only amplify this issue, underscoring the critical need for proper waste management and disposal to enhance sustainability in healthcare.2
Overall as consumer awareness and regulatory pressure to be more eco-conscious increases, adopting sustainability practices into healthcare becomes a necessary factor. A growing number of diagnostic developers have committed to the UN-backed “Race to Zero” initiative, pledging to achieve net-zero greenhouse gas emissions by 2050.3
Strategies that support sustainable practices focus on using resources efficiently to maximize productivity and eliminate waste. For diagnostic companies, this translates not only to helping the environment but also to reducing costs, building resilience, and providing a significant competitive advantage. There are several different approaches to enhance an assay’s sustainability and in this blog, we will delve into four key strategies that can make a significant impact.
1. Consider alternative sample types & patient self-collection
Diagnostic blood samples collected by phlebotomy are the most common type of biological specimens sent to laboratories. According to a study published in 2020 examining the carbon footprint of pathology testing for five common hospital pathology tests, most carbon dioxide equivalent (CO2e) emissions are associated with sample collection (range, 60% for full blood examination to 95% for coagulation profile)4. Replacing venous blood collected by a phlebotomist for patient self-collection of capillary blood using a fingerprick or other methods would immediately eliminate a significant portion of these carbon emissions. It would remove the need for PPE, a key contributor to CO2e emissions, and for patient travel to a collection site.
In addition, alternative sample types such as saliva and urine, where the analyte remains stable in the matrix and is not sensitive to temperature and other environmental factors, are ideal for reducing carbon emissions as they are easily transported by mail or post and do not require refrigeration. They also generally require less sophisticated sample collection devices, reducing the amount of hazardous waste produced in the collection process.
2. Lyophilize assay reagents to reduce CO2 emissions produced from cold chain transport and storage
Diagnostic manufacturers often produce reagents centrally and distribute them globally, resulting in the consequential impact of CO2 emissions. Some of this global distribution necessitates cold-chain shipping and storage to maintain product integrity.5 By lyophilizing reagents, – they remain stable at room temperature thereby removing the need for cold-chain transport, storage, monitoring, and the waste produced from cold-chain packaging6. This drastically reduces a test’s carbon footprint. In addition, lyophilized assays extend an assay’s shelf-life, reducing waste and associated costs on multiple levels.
3. Reduce the steps and materials used in an assay workflow
Plastics and consumables make up a large part of an assay’s environmental footprint, especially single‐use items. Currently, most molecular qPCR tests require RNA or DNA extraction prior to detection; however, extraction is expensive, time-consuming, and requires technical expertise. Eliminating this step in favor of direct detection can streamline the diagnostic workflow, reduce assay complexity, accelerate specimen processing, reduce time to results and decrease reagent usage.
Generally, improving an assay’s efficiency can reduce its carbon footprint. Strategies such as removing steps in a protocol, minimizing the volume of reagents used, and multiplex testing can be employed to reduce the hazardous waste produced in performing a test. However, to implement these strategies, the reagents used must meet certain criteria. High-concentration reagents are required to reduce assay volume, inhibitor-tolerant master mixes must be formulated to achieve a high sensitivity without nucleotide extraction and uniform multiplexing requires a mix to perform uniformly, with unbiased amplification of different targets.
4. Use animal-free reagents whenever possible
In recent years, there has been a growing movement towards developing animal-free reagents, with the European Medicines Agency (EMA) spearheading the implementation of the 3Rs principles (Replace, Reduce, Refine) to minimize the use of animals in diagnostics. These alternative reagents aim to improve assay performance and reproducibility, and reduce cost while also contributing to a more sustainable and humane future. Using animal-free reagents can improve assay carbon footprint, by reducing the environmental impact associated with sourcing and processing animal-derived materials. This approach eliminates the need for raising and maintaining animals, reducing land use, water consumption, and greenhouse gas emissions associated with animal agriculture. Additionally, it minimizes the use of chemicals and resources involved in processing animal-derived reagents.
Blockers, such as Mouse IgG, are used in immunoassays to reduce non-specific binding and other interference that can lead to false positive results. These reagents can be used in large amounts and require mice to be immunized in order to harvest the antibodies they produce.
The process has raised ethical concerns and prompted the exploration of alternative, animal-free methods for immunoassay blocker production.
In addition, antibodies, antigens, and enzymes from animal-free sources are increasingly available, whether as recombinant proteins/enzymes or derivatives from plants or bacteria. Animal-free reagents generally exhibit minimal variability and a lower risk of contamination compared to animal-origin counterparts. Their adoption represents a pivotal step towards ethical and sustainable practices in diagnostic manufacturing.
Making tests more sustainable by design
Environmental sustainability is often described as a hierarchy of waste reduction: avoid, reduce, re‐use, and recycle7.
However, for pathology testing, the opportunities for re‐using or recycling items are limited due to infection control. The main opportunities for reducing waste and CO2 emissions involve utilizing sustainable materials, optimizing processes, reducing reagent volumes, and employing multiplex testing.
At Meridian, we believe sustainability starts with us. Across our entire operation, we strive to integrate the principles of sustainability and ethical practices into our business to deliver innovative, eco-conscious products to our customers and help empower them to achieve their sustainability goals. Some of our leading innovative and environmentally conscious products include:
- Specimen-specific mixes formulated for sensitive detection from alternative sample types such as saliva, urine and stool
- Lyo-Ready and Air-dryable™ master mixes as well as glycerol-free enzymes designed for creating ambient-temperature stable assays
- High-concentration enzymes suited to assay miniaturization
- Inhibitor-tolerant master mixes developed for direct amplification from crude lysates
- Animal-free immunoassay blockers; HAMA, HA and Rf
References:
1. Street, A., Vernooij, E. & Rogers, M.H. Diagnostic waste: whose responsibility?. Global Health 18, 30 (2022). https://doi.org/10.1186/s12992-022-00823-7
2. Why the medical industry should tackle single-use diagnostic waste. Medical Plastics News (2022)
4. McAlister, S., et al., The carbon footprint of pathology testing. Med J Aust; 212 (8): 377-382. (2020) doi: 10.5694/mja2.50583
5. The cold chain innovates to meet post-COVID demands. Nature (2022)
6. Whyte, S. Building a Greener Supply Chain: Key Considerations for Cold Chain. PharmTech 64 (5): 34-37. (2022)
7. Sustainable Materials Management: Non-Hazardous Materials and Waste Management Hierarchy. United States Environmental Protection Agency.