FDA CDRH maintains a webpage for De Novo Summaries: Evaluation of Automatic Class III Designation De Novo Summaries. This is for devices that are novel but low to moderate risk ((not ideal for 510(k)s and PMA would be overly burdensome). There are now two options for de novo classification. One is in response to an Not Substantially Equivlaent (NSE decision) in FDA in response to a 510(k) submissions (this used to be the only option). The second is if there is no suitable predicate device a de novo request could be submitted first without a 510(k) for FDA to make a risk based classification. The FDA webpage is at the link provided. Looking at current and past determiniations can be helpful when evaluating a device for suitability for a de novo.