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Biological Equivalency: When is “same” the same?


In this episode, our hosts are joined by NAMSA Toxicologist, Michelle Kelly, to discuss the ever-elusive biological equivalency claim. The discussion focuses on how to maintain the balance of the risk and benefit of a medical device without stalling innovation. We also explore equivalency and how it is not only a key concept to the risk analysis, but also a challenging concept to prove.

Discussion points include:

  • Equivalence in the 10993 Series, including ISO 10993-18 Annex C
  • Equivalence under the MDR
  • Variances in the EU from one Notified Body to another
  • Challenges with demonstrating and establishing overall MDR equivalence
  • The concept of “same” and how it is interpreted by regulators

“This is often a controversial topic.” – Sheri Krajewski

“You not only have to think about equivalency per 10993-1, but also think about it as one aspect of equivalency that is sitting in the MDR.” – Don Pohl

“Equivalency is one of the key principles that sits in 10993-1.” – Don Pohl

“To think of equivalence as a concept rather than an equation is the best thing to do.” – Michelle Kelly

“We have that word “same” sneaking up on us. I can see that being interpreted differently by reviewers and regulators.” – Don Pohl

“When we developed it [Annex C of 10993-18], we were trying to define toxicological equivalence to help out the working group writing 10993-17.” – Michelle Kelly


*Please note that the opinions discussed throughout the podcast are their own and do not reflect that of their current or former employers.

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Meet the Speakers


Michelle Kelly; Toxicologist, NAMSA

Michelle Kelly recently joined NAMSA in August 2021 as a Toxicologist working in the Biological Safety and Validation Team. Prior to NAMSA, she was the Biological Safety Manager at UK Competent Authority, MHRA. Her responsibilities included serving as Principal Lead for clinical trial applications for biological safety, providing expert biological safety advice and directing the Regulatory and Safety and Surveillance Teams on compliance, vigilance and Notified Body matters. Michelle also d continues to work with key stakeholders toward the development of international standards to help innovation to the UK market. She is currently the Chair of CH/194, a committee responsible for the UK input to ISO/TC 194 and CEN/TC 206 for standards relating to biological evaluation of medical devices.

Michelle has a BSc in Biomedical and Advanced Materials from University of Limerick in Ireland, an MSc in Applied Toxicology from University of Surrey and she is a European Registered Toxicologist.

Sheri Krajewski; Product Marketing Manager – Biological Safety, NAMSA

Sheri joined NAMSA in 2003 and currently serves as Global Product Marketing Manager of Biological Safety. She has supported customers in a variety of commercial operations and management roles, and was an integral leader in the development of NAMSA’s biological safety consulting business. Additionally, Sheri created the much sought-after NAMSA Training Series for the biological evaluation of medical devices. Prior to NAMSA, Sheri was the marketing lead for a mechanical fatigue laboratory and consulting business where she worked primarily with cardiovascular implant manufacturers. Sheri holds a Bachelor’s Degree from the University of Nebraska.

Don Pohl; Principal Product Development Strategist, NAMSA

Don has over 25 years of experience in the preclinical evaluation of medical devices for biological safety. During his career, he has held a variety of positions ranging from laboratory supervision/management, GLP Study Director, Technical Specialist for Laboratory Information Management System, Technical Specialist and Project Manager for Biological Safety and Biological Risk Assessment consultation. He has specific expertise in the evaluation process outlined in ISO 10993-1, as well as the expectations of the U.S. FDA and other global regulatory bodies in their interpretation of the biological safety evaluation of medical devices. Don holds a Bachelor’s degree from Ohio State University.