Design Validation / Verification of Medical Devices
CE marking and FDA registration of medical devices and IVDs requires design validation and design verification.
Design verification: have the component parts been design correctly to deliver their intended function correctly and safely?
Design validation: does the finished device deliver its intended function correctly and safely?
An example of how best practice may subtly differ between verification and validation is biocompatibility testing. The biocompatibility of the entire device as it is presented to an end user must be validated; this is usually effected by testing of the sterile market ready device according to ISO 109931. But, it is very desirable that any exposed materials are individually biocompatible, this can normally be verified using the material manufacturer’s biological safety data (or materials characterisation to ISO 10993-182) as the product design progresses.
The American and European requirements are usually very similar. Assuming that your design and production is all correct under ISO 134853 certification, then addressing the Essential Requirements4 will validate the design for CE marking. There may be specific FDA Guidance for your device which indicates areas in need of increased vigilance. In the majority of cases this will coincide with any ISO or ASTM standards which refer specifically to the device concerned. This is not always the case. Taking bone cement as an example, ISO 5833:20025 is largely concerned with the liquid properties of the cement prior to setting and its static properties once set. Whereas the relevant FDA draft Guidance6 references a number of ASTM standards for assessing for static and fatigue properties of the set material. There is also a greater emphasis on chemical analysis and its change with time, in the FDA document. Risk analysis is always required throughout to highlight any other areas that might require safety validation. For more complicated devices ISO 623667 gives advice on ease of use.
Laboratories such as Medical Engineering Technologies Ltd8 (www.met.uk.com) can assist medical device developers to conduct their risk analyses, and to understand the product standards and Essential Requirements for their product. The laboratory can then draw up a validation and testing plan to include performance and safety testing, biocompatibility, chemical analysis and shelf life stability.
Ref 1 ISO 10993-1:2009 Biological evaluation of medical devices -- Part 1: Evaluation and testing within a risk management process
Ref 2 ISO 10993-18:2005 Biological evaluation of medical devices -- Part 18: Chemical characterization of materials
Ref 3 ISO 13485:2003 Medical devices -- Quality management systems -- Requirements for regulatory purposes
Ref 4 Directive 93/42/EEC on Medical Devices (MDD), Annex 1.
Ref 5 ISO 5833:2002Implants for surgery -- Acrylic resin cements