The FDA's risk-based Class I/II/III system, the 510(k) substantial-equivalence pathway versus PMA versus De Novo, predicate selection, and why regulatory strategy has to be decided before the first prototype exists rather than written up afterward.
Every medical device legally sold in the United States is sorted into one of three FDA risk classes under 21 CFR Part 860, and that single early assignment determines everything that follows: which submission pathway applies, how much clinical and bench evidence is required, and how tightly the design controls process later has to document traceability. This module works through the 510(k) pathway's substantial-equivalence logic against a predicate device, the PMA pathway's independent safety-and-effectiveness burden for Class III devices, and the De Novo pathway that exists for novel devices with no valid predicate but only low-to-moderate risk — including why De Novo has become the default route for many software-driven and AI-enabled devices today.
The module closes by treating regulatory strategy as a day-one design input rather than a submission-writing exercise performed after engineering is finished: target classification, intended pathway, and even specific predicate candidates are decided before a prototype is built, because they set the design inputs the design controls process in Module 2 must trace against and the residual-risk threshold the risk management file in Module 3 is ultimately judged against.