Unreasonable risk

The test is framed from the patient's perspective, which links it to FDA's use of patient preference information. A risk can be high and still not unreasonable if informed patients would accept it for the benefit.

For the purposes of this guidance “unreasonable risk” refers to a risk that no set of reasonable patients would be willing to endure to achieve a probable benefit.

FDA guidance: Factors to Consider When Making Benefit-Risk Determinations in Medical Device Premarket Approval and De Novo Classifications (August 2019), Footnote 19