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Oh No, Another Failed Cyto!


In this episode, our guests are joined by Melissa Cadaret, NAMSA’s Director of Global Compliance and Process Improvement, to discuss the ever-confusing ‘cytotoxicity failure.’ Manufacturers can sometimes experience confusing results due to unexpected cytotoxicity results. What must manufacturers understand in order to properly navigate the cyto failure, whether expected or unexpected? Listen in as our experts discuss these challenges and best practices derived from NAMSA’s thousands of cytotoxicity tests and results.

“I would say generally, we see some type of cytotoxicity failure weekly.” – Melissa Cadaret

“Cytotoxicity is not really an endpoint. It’s a screen.” – Sheri Krajewski-Bibins

“It is what it is, and it is what it’s not.” – Don Pohl

“It’s the only biological effect listed as an overall screen for biocompatibility.” – Don Pohl

“Things like copper and antimicrobials really wreak havoc and contribute to a lot of cytotoxicity failures. Some of your residues from your cleaning and in processing aspect are also a huge culprit.” – Melissa Cadaret

“It might have been expected. You can get pretty good at predicting cytotoxicity.” – Don Pohl

Discussion points include:

  • What does it mean when one receives a failed cyto result?
  • What useful information can you gather from a cytotoxicity test?
  • What materials and devices can typically have problems associated with cytotoxicity tests?
  • What should you do if you know your material is going to fail cyto?


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

Also be sure to check out our Biocompatibility Strategy Navigator.

Meet the Speakers


Melissa Cadaret; Director of Global Compliance and Process Improvement, NAMSA

Melissa Cadaret is the Director of Global Compliance and Process Improvement at NAMSA. Her experience includes serving as the Director of Analytical Services and Biocompatibility Laboratory Operations and Site Leader for NAMSA’s Global Headquarters in Toledo, Ohio. With more than 15 years of biocompatibility experience, Melissa is an expert on U.S. ISO TC 194: Biological Evaluation Medical Devices ANSI / AAMI/ ISO 10993. Ms. Cadaret holds a Master of Science degree in Molecular Biology from Bowling Green State University and Bachelor of Science degree in Biology from Southern Illinois University.

Sheri Krajewski-Bibins; 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 USFDA and other countries in their interpretation of the biological safety evaluation of medical devices. Don holds a Bachelor’s degree from Ohio State University.