Top 4 ways to improve sustainability in diagnostic testing

Dr Nick Collier, CTO Medical, Sagentia Innovation, explains why diagnostic testing is ripe for sustainable development.

Diagnostic tests inform 70-80% of healthcare decisions. They also account for a significant portion of the sector’s waste and carbon footprint. With the environmental impact of healthcare facing greater scrutiny, there’s a strong case for enhancing R&D with sustainability considerations. Handled well, this can have a positive impact across both environmental and commercial performance.  

As the sector starts to consider sustainability alongside patient safety, there are new commercial opportunities for companies that can strike an effective balance.  

Sustainability in the diagnostic process 

Diagnostic waste accounts for a tenth of all medical waste, and since much of it is infectious or hazardous, reuse and recycling are challenging. At present, cost and performance are the main considerations shaping the development of diagnostic devices. How can we make sustainability integral to the process without undue compromise of these factors? 

The first step is to consider the full lifecycle of a laboratory diagnostic test, identifying environmental impacts at each stage. For instance, the hazardous and/or infectious nature of waste brings end of life complications. Disposal of sharps, patient specimens, contaminated equipment, and harmful chemicals needs to be handled with great care. Consequently, most diagnostic waste is incinerated, with 1g of waste generating up to 3g of CO2. In fact, greenhouse gases are emitted at every stage of the diagnostic test lifecycle, so exploring ways to reduce these emissions is a good place to start.   

Innovating around blood testing 

An Australian study published in 2020 The carbon footprint of pathology testing focused on five common hospital pathology tests. It determined that sample collection and phlebotomy dominated the overall carbon footprint, and although CO2 emissions per test were small, the volume performed meant the cumulative carbon footprint was significant. We’ve used the findings from this study as a platform to demonstrate how R&D efforts can be directed towards the reduction of CO2 emissions. 

For instance, equipment used for sample collection accounted for around half of the overall carbon dioxide equivalent (CO2e). Waste incineration represented a significant portion too. The CO2e of the diagnostic process itself varies according to the test and the amount or type of reagent required. Based on these insights, we identified four strategies to improve the sustainability position of blood testing.  

1. Collect less blood 

In the main, blood tests involve a venous blood draw into vacutainer tubes. The volume collected is typically 4mL, yet many diagnostic tests only require a small portion of this – a complete blood count can be performed using 100μL. If the volume of blood collected was reduced to 500μL it would still be possible to perform multiple tests, but a smaller vacutainer could be used. Based on the figures in the Australian study, this would immediately reduce carbon emissions linked to ‘needle holder and collection tube’ and ‘incineration of hazardous waste’, effecting a 27% reduction in CO2e for a whole blood count, and a 38% reduction for clinical chemistry. These wins could be taken further if the overall number of blood draws per patient was reduced, for instance by conducting multiplex testing on samples. 

2. Focus on reagents  

Manufacturing the reagents that play a critical role in many blood tests is expensive, and production must be closely monitored for quality control and consistency. Vendors tend to produce reagents centrally and distribute them globally, which makes a notable contribution to the CO2e of diagnostic tests which require them. According to the Australian study, reagents used in a whole blood count test account for around a third of the total CO2e. 

A large portion of a reagent is ultrapure water, so the use of concentrated formulations for reconstitution in the laboratory could cut the carbon emissions linked to transportation. We calculated that a x10 concentrate shipped via sea from Singapore to Australia would deliver a 4.5x CO2e reduction. Dilution at point of use would add a new burden of responsibility to pathologists and introduce a potential failure point, but this could be addressed using an automated process.   

It's also worth exploring ways to reduce the amount of reagent used. At present, lab instruments typically require 100μL of blood per test while point of care technologies only need 5-30μL. If lab instruments were adapted or redesigned to operate with smaller volumes of blood, it would result in a corresponding reduction in the amount of reagent required.  

3. Consider self-collection 

Swapping the venous blood collected by a phlebotomist for patients’ self-collected capillary blood could also offer carbon reduction benefits. Self-collection would negate the need for PPE which is identified as a significant CO2e element in the Australian study. This approach may also reduce the need for patient/phlebotomist journeys, bringing further carbon savings.  

Devices for the self-collection of blood on market at present haven’t been designed with sustainability in mind. However, there is scope for innovation focused on optimising the materials used, reducing the portion wetted by blood, and making devices safer to dismantle.  

4. Improve recovery of device components 

Reducing the volume of blood collected has the potential to reduce CO2e quite significantly, but further improvements could be made if more components used in sample collection devices could be reused or recycled. At present, all components enter a single waste stream destined for incineration. However, an automated system for the separation and disinfection of waste could allow some of the plastics to be recovered. Use of well-characterised plastics could allow non-biological waste from laboratories to be disinfected, separated, and channelled into commercial recycling streams. As with the dilution of reagents, this could be facilitated with automation and high throughput analysers.  

Collaboration across the diagnostic lifecycle 

Together, the four approaches outlined here could reduce the CO2e of blood tests by around 50%. Whilst these examples are theoretical, they are technically feasible. Given the complexity of healthcare systems, bringing approaches like this to life will require industry partnerships or vertical integration strategies. Likeminded companies that understand and align with the need for environmental sustainability have opportunities to collaborate to win market share, derive cost savings, and deliver benefits for individual patients and wider public health.