How to read an FDA 513(g) response

A 513(g) request is a narrow, specific question a company asks FDA in writing: given this description of our device, what classification and regulatory pathway would apply? FDA’s written response answers that question, and only that question. It is one of the more useful documents in a device company’s file precisely because it is so limited — read for what it actually says, not for what a company later hopes it meant.

What a 513(g) response actually answers

FDA’s response to a 513(g) request typically states a classification — Class I, II, or III — and, where one applies, a proposed product code and the regulation number that governs it, based entirely on the device description the company provided. That is the whole scope. It does not evaluate whether the device is safe or effective, does not review any data, and does not tell you whether a future 510(k) or De Novo submission for that device would succeed. Companies sometimes request one specifically to get a documented, citable answer before committing engineering and clinical resources to a pathway — the same kind of pathway question the 510(k) course covers in more depth once a predicate is in view.

Why the caveats in the letter matter

FDA’s 513(g) responses are written carefully, and the qualifying language is doing real work, not padding. A response that says the classification depends on “the intended use as described” is telling you the answer changes if the labeling or claims change later. A response that declines to commit to a single product code and instead lists two or three possibilities is telling you the description didn’t narrow the field enough — not that FDA is being unhelpful. None of this is a rejection. It is FDA giving you exactly as much certainty as the request supports, and no more, which is also why the request itself is worth writing carefully: the device description you submit is the only thing the response is actually about.

A 513(g) response is a small, cheap way to get a documented answer to a question that otherwise gets argued informally and remembered differently by everyone in the room. Used for what it is, a classification opinion rather than a clearance, it is one of the more efficient tools available before deeper resources go into a product classification decision that’s harder to unwind later.