About Critical Values

If you were to ask someone for a definition of sustainability in healthcare, you would not be hard pressed to find one. Sustainability has become a topic du jour, alongside current global concerns like infectious diseases and Anti-Microbial Resistance (AMR). In essence, “Environmental sustainability in healthcare focuses on improving, maintaining, or restoring individual and population health while minimizing adverse effects on the environment and taking advantage of opportunities to enhance and repair it for the benefit of both current society and future generations.”¹ 

This focus has gained significant traction in recent years, largely due to heightened awareness of the healthcare industry’s environmental footprint. While the concept of environmental sustainability is not new, it came into the forefront during the COVID-19 pandemic, which highlighted critical areas where healthcare practices could improve. 

Sustainability lessons from COVID-19 

Two distinct observations became apparent during the pandemic. The amount of waste generated in the form of Personal Protective Equipment (PPE) such as gowns, masks, and gloves were unlike anything seen before on a global scale.² Secondly, the amount of waste produced from COVID-19 diagnostic tests was staggering. Ongaro and colleagues reported that COVID-19 point-of-care tests exceeded 1 billion, while in comparison, malaria was estimated at 412 million, HIV at 2.5 million, and TB at less than 3 million.³ Their research highlighted the significant environmental impact of these laboratory tests, particularly in low- and middle-income countries (LMICs).  

As laboratories scale up services to meet global diagnostic demands, the emphasis on sustainable practices must move from being a side note to a core operational priority. 

Sustainability in histology  

Interestingly, histology laboratories have been practicing sustainability for decades through solvent recovery distillation, though awareness of this practice has been limited in LMICs. The technology involves recycling solvents like alcohol, acetone, and xylene for reuse, offering significant environmental and cost benefits. This technology is even more critical in LMICs as most lack access to hazardous waste management companies that could collect, transport, and treat/dispose of the solvent waste. 

Histology labs of solvents. 

How solvent recovery works 

1. Heating – the waste solvent is heated to its boiling point.

2. Vaporize – the solvent boils away and is collected as vapor.

3. Condense – the vapor is cooled and condensed back into a liquid.

4. Collect – the recovered solvent is collected in a clean tank for reuse.  

It is crucial to segregate solvents separately as mixing them introduces contamination that disrupts the distillation process. It can prevent the system from effectively separating and recovering the individual solvents, reducing the quality and usability of the reclaimed solvents. By maintaining strict segregation of solvents, laboratories can ensure the efficiency and success of the recovery process. 

Key sustainable benefits include: 

1. Reduction in solvents procured: Alcohol recovery rates can reach up to 99 percent, while other solvents such as xylene and acetone achieve rates between 85 percent and 90 percent. This significantly reduces the need to purchase new solvents. 

1. Lower disposal costs: Reducing the volume of hazardous waste lowers costly off-site disposal services. 

1. Optimized storage: Recovered solvents require less storage space compared to bulk quantities of unused or spent solvents. 

1. Environmental impact: Prevents the release of harmful chemicals into sewage systems or the environment. 

Scalable solvent recovery units are available and enable laboratories to adopt this practice seamlessly. These systems can also recover formalin/formaldehyde solutions, making them versatile for sustainable lab operations. 


CBG solvent recycler

Unlike many other technologies designed to treat laboratory and healthcare waste, solvent recovery units stand out as a truly sustainable solution. 

Tissue digestors 

In addition to solvent recovery, tissue digestors represent another technology for implementation in histology labs. Tissue digestors use alkaline hydrolysis, a process initially developed to manage prion-infected animal remains.4 Their application has expanded to management of a broad group of animals as well as human soft tissue.5  

Tissue digestion process 

• A caustic agent (potassium or sodium hydroxide) and water are combined with the tissue in a sealed chamber. 

• The system is heated to approximately 100°C (non-pressurized) or up to 150°C (pressurized), reducing tissue into a liquid that can be safely discharged into sanitary sewers. 

• Pressurized systems process waste in under three hours, while non-pressurized systems may require up to 24 hours. 

The result is a liquid waste product that can be safely discharged into sanitary sewers, provided its high biological oxygen demand (BOD) is managed appropriately. Large volumes may require discharge permits to ensure compliance with local wastewater regulations. 

Unlike traditional methods such as incineration, cremation, or burial, tissue digestors offer a more environmentally friendly solution. They allow for waste treatment directly at the point of generation, reducing the carbon footprint associated with transporting waste to off-site facilities. Tissue digestors can also neutralize formalin from fixed tissue samples, making them a versatile solution for histology labs striving for sustainability. 


PRIsystems tissue digestor

Medi-Clave tissue digestor 

Expanding laboratory sustainability efforts 

The growing momentum behind laboratory sustainability has fueled the emergence of numerous organizations offering innovative solutions, including, but not limited to:*  

Research Recycling: Facilitates the reuse and recycling of laboratory materials. 

My Green Labs: Promotes sustainable practices and certifications within laboratory settings. 

Grenova: Focuses on washing and reuse of lab consumables, such as pipette tips and microplates, to reduce plastic waste. 

Polycarbin: Develops sustainable alternatives for lab plastics, reducing dependency on single-use materials. 

Diversified Bio: Provides comprehensive waste management and recycling services for laboratories.  

The growing momentum behind laboratory sustainability has fueled the emergence of numerous organizations offering innovative solutions for the reuse and recycling of laboratory materials, sustainable practices and alternatives, and comprehensive waste management and recycling services for laboratories.  

Histology laboratories are positioned to champion sustainability through practical and impactful measures. From solvent recovery to tissue digestors, the sector already has solutions to significantly reduce its environmental footprint. As interest in sustainability continues to rise, integrating these technologies and fostering innovation will play a pivotal role in creating greener, more responsible laboratories. 

By integrating these technologies, laboratories can actively contribute to a more sustainable environment while maintaining operational efficiency. Sustainability is no longer just a buzzword in healthcare, it is a responsibility and opportunity to make a meaningful impact. 

*The products listed in this article are not an exhaustive list. Inclusion in this article does not constitute an endorsement of product or company by ASCP. 

References 

1. https://alirahealth.com/education-hub/environmental-sustainability-and-healthcare-examples-from-worldwide-markets/

2. https://www.who.int/publications/i/item/9789240039612

3. https://pubs.rsc.org/en/content/articlelanding/2022/lc/d2lc00380e

4. https://www.avma.org/javma-news/2004-04-01/breakdown-biodigesters

5. https://pmc.ncbi.nlm.nih.gov/articles/PMC9134473/