Emergency use isn't defined in Part 812

A physician facing a dying patient and an investigational device that might help reaches for one phrase: compassionate use. FDA’s own regulations don’t organize the problem around that phrase. They split it by patient count and by how much time is on the clock — and the term for the most urgent case isn’t even defined in the part of the Code of Federal Regulations that governs investigational devices.

Three sizes, three different mechanisms

FDA’s own guidance sorts expanded access to an investigational device into three tracks. Emergency use covers one patient, in a genuinely life-threatening situation, with no time to run the ordinary process. Compassionate use covers a patient, or a small group, who doesn’t meet a study’s enrollment criteria but could plausibly benefit from a device already under an active investigational device exemption. A Treatment IDE covers a larger population that needs access before a marketing decision, processed as its own submission under 21 CFR 812.36. Same underlying problem — a patient outside a trial who needs a device that isn’t cleared or approved — three different mechanisms, chosen by patient count and by how much time there is.

The word that isn’t in Part 812

Part 812 is where the investigational device exemption itself lives — where a sponsor’s IDE application, a Treatment IDE’s criteria, and a device study’s reporting duties are all defined. “Emergency use” is not one of the terms Part 812 defines. It is defined at 21 CFR 56.102(d), inside the institutional review board regulations, as use of a test article on a human subject in a life-threatening situation with no standard acceptable treatment available and no time to secure IRB approval before proceeding. The device regulation assumes the emergency happened; the IRB regulation is where the term gets its legal shape. A reviewer who searches Part 812 for “emergency use” and comes up empty has not missed anything — the definition was never filed there.

The device rule assumes the emergency. The IRB rule is where the word itself lives.

Three clocks, not one

The three mechanisms don’t share a clock either. Emergency use, by definition, happens before any of FDA’s ordinary review windows can run; the obligation that follows is a report, not a request. If the device is already under an IDE, 21 CFR 812.35(a)(2) requires the sponsor to notify FDA of the emergency use within five working days after the fact. A Treatment IDE runs the opposite direction: 21 CFR 812.36(d) lets treatment use begin thirty days after FDA receives the submission, unless FDA acts sooner to approve, modify, or block it — a passive-clearance clock, built for a decision FDA has time to make before use starts. Compassionate use for a single patient under an existing study’s IDE sits in between, and faster than either: FDA’s own guidance describes typical turnaround around fifteen days, sometimes as little as one, because the request rides on a study FDA has already reviewed. Naming the wrong mechanism doesn’t just misfile the paperwork. It attaches the wrong clock to a request that may not have days to spare.

The practice

Before calling a request “compassionate use,” establish the three facts that actually route it: whether an IDE already exists for the device, how many patients need access, and how much time is available before use has to start. Each answer points to a different mechanism, a different CFR section, and a different clock — and only one of the three, emergency use, is defined somewhere a search of Part 812 alone will never find. Which mechanism fits a specific patient, and whether a specific use meets its criteria, is a determination for the treating physician, the sponsor, and the reviewing IRB, never a call this post is making.

None of FDA Radar’s four sources — Federal Register notices, 510(k) clearances, device recalls, CDRH warning letters — carries an emergency-use notification, a compassionate-use request, or a Treatment IDE; per what we monitor and how often, none of the three ever produces a public record any of them would catch.