I'd like to know if there is anything in US law that gives the FDA authority over medical devices which aren't marketed; and where that is in the law specifically. I did a quick search of Title 21, Chapter 9 (the FD&C Act) but couldn't find a concise description of what medical device-related activities the act regulates, specifically.
It is notable that the different kinds of approvals for devices are called Premarket Notification (510(k)) and Premarket Approvals (PMA).
If the FDA only regulates marketing, the definition of "marketing" may also require some elaboration. If I make a device and give it away for free, am I marketing it? In other words, does "market" refer to the device changing hands in any way, or specifically to a sale? What if I make it and use it myself? (it never changes hands) What if a hospital makes it and uses it? (it stays within the same entity/organization)
Alternately, does marketing refer to making a claim that something can be used as a medical device? (intended use) What if I make something which has an obvious medical use, and sell it or give it away, but never advertise (or describe) the medical use? (eg, I might make tongue depressors, but sell them as "pieces of wood" or "coffee stirrers")
Note: 21CFR807 defines "commercial distribution" as "distribution of a device intended for human use which is held or offered for sale" - which seems pretty clear, it would not cover anything other than sale (eg: a donation). I still can't find a definition of "marketing" though.
UPDATE: There is an interesting aspect to the "intended use" argument which I didn't realize until just now. Medical devices are commonly made by third parties (contract manufacturers) for another company that sells them to the public. The contract manufacturers in general do not need (or get) FDA clearance/approval, even though they are clearly making and selling medical devices. It seems the difference is that the contract manufacturers are not claiming any intended use for the devices - they're just making whatever the other company tells them to make. The contract manufacturers do need to register with the FDA ("establishment registration") but do not appear to need any approval to make a specific device; presumably because they aren't "marketing" anything.