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When to Go with In Vitro: Your Irritation Questions Answered


In this episode, our hosts answer listener questions regarding the new ISO 10993-23:2021 from NAMSA’s February 3, 2021 webinar.

The standard recommends that In Vitro testing be completed prior to In Vivo testing, warranting many questions about how to deal with legacy data, regulatory acceptance and timelines. Our hosts will provide podcasters a full episode of responses, possible scenarios and potential recommendations.

“This is an extraction-based evaluation and you will be creating and dosing extracts in most cases. There is not a direct contact equivalent for the In Vitro like there is In Vivo.” – Don Pohl

“In the past, if you used the intracutaneous or primary skin appropriately, then this In Vitro test is for you.” – Don Pohl

“We have heard from one Notified Body that they are going to be giving a one-year grace period, [meaning the standard just issued in January 2021], they are giving folks until January 2022 to switch to the In Vitro method.” – Sheri Krajewski-Bibins

“Similar concept to Part 1, if you already have your data collected, it might be worth mentioning in your biological evaluation report. If you feel like you need to [mention] regarding the timing of events, that testing was already planned, executed and performed prior to [Part] 23 issuing, therefore, the In Vivo method was utilized.” – Don Pohl

“If you are having a pre-sub with the FDA, maybe have that conversation too that you would like to do the In Vitro method, and see what they tell you even though there is no official position.” – Sheri Krajewski-Bibins

“The standard has the one sentence that says In Vivo may be needed post In Vitro to clarify, but it doesn’t necessarily say because you failed or found an irritant….. I think you need to still be careful on your due diligence. Look at your failure in the In Vitro level, understand the materials, your manufacturing process and confirm you didn’t miss anything.” – Don Pohl

Discussion points include:

  • What is in the new 10993-23:2021 and what is it not
  • How to know if an In Vitro irritation test is right for an implant
  • Regulatory agency answers on when they will expect In Vitro irritation
  • Limitations of the In Vitro assay
  • What to do if you receive an irritant response in the In Vitro assay


*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


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 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.