💥 A Meteorite Strikes and the Sky Falls on Us – The Art and Science of Defining Worst-Case Tests in Medical Technology.
We believe that there is a lack of guidelines around the topic of worst-case testing in the medical device industry.
In this short but comprehensive article we give you an essential overview of what you need to consider when doing worst-case testings in MedTech.
Countless standards and guidelines talk about "worst-case", either from a use, product, process, or test perspective. Even though we all use the term "worst-case" in an inflationary manner, we know little about it.
An excerpt of standards that include worst-case considerations are:
ISO 10993-1
ISO 11607-1
ISO 19227
ASTM F3263
ASTM F3127
and many others
Unfortunately, we often refer to a "worst-case" without really having it defined nor documented. In the following, we will give you some ideas and guidance on what to consider when defining a worst-case and how to document it.
1) Worst-Case: Introduction
Highlight the importance of worst-case scenarios for safety, effectiveness, and compliance. Stress the need for a versatile, systematic approach applicable across various product families and/or processes.
2) Worst-Case: Scope and Purpose
Clearly define the scope of the worst-case scenario, specifying its intended application (e.g., process validation, design verification, cleaning validation, etc.).
State the purpose, emphasizing risk mitigation, compliance, or process optimization.
3) Worst-Case: Identify Critical Parameters
Identify the key parameters that significantly influence safety, efficacy, or compliance of the product or process.
Consider factors such as materials, environmental conditions, user interactions, and potential failure modes.
4) Worst-Case: Assess Variability
Evaluate the variability associated with each critical parameter.
Determine the lower and upper limits, considering both typical and extreme conditions.
5) Define Worst-Case Conditions
Develop a matrix or framework that combines critical parameters and their variability.
Select worst-case conditions by identifying the most extreme values or combinations of parameters from the matrix.
An example of worst-case testing
Please note that the matrix provided is solely an illustrative example and is neither accurate nor exhaustive in representing the full scope of a specific scenario.
5) Worst-Case: Documentation and Rationale
Document the rationale behind the selection of worst-case conditions (see Table 1).
Include detailed information on how each parameter was evaluated and why specific conditions were chosen.
6) Worst-Case: Monitoring and Adaptation
Emphasize the need for ongoing monitoring and reassessment of worst-case scenarios (e.g., product and/or process changes; is the worst-case still applicable?).
Acknowledge that technology, regulations, or other circumstances may change, requiring updates to worst-case definitions.
We wrote this article due to the lack of guidelines around that topic. Many standards call out worst-case considerations with sometimes limited information.
This article should help you navigate, document, and monitor the task of worst-case testing.
What is your experience with worst-case testing? Do you have specific questions questions or valuable insides on this topic? As always, we appreciate if you leave us a comment below.
Author: Simon Föger
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