I’ve been working in regulatory for a company in which biocompatibility of device materials has been pretty straightforward and understood by all for many years. Annex A in ISO 10993-1 and FDA General Program Memorandum - #G95-1 is all you need. Check the chart for our device intended use and see that irritation testing, sensitization testing and cytotoxicity testing are required for any new device materials prior to introducing them into the market. Not only did our regulatory folks clearly understand these requirements, but our project teams were also onboard. If engineering wanted to change materials or change the material color or tint, they would contact a toxicologist to perform these three necessary tests. End of story.