FDA Review Process & MDUFA Timelines
Step 1 — Submission and acknowledgement
FDA acknowledges receipt of a 510(k) within 10 business days and assigns a K-number (e.g., K241234).
Step 2 — Acceptance review (Refuse to Accept)
Within 15 business days, FDA performs an acceptance review to verify that the submission contains all required elements. If the submission is incomplete, FDA issues a Refuse to Accept (RTA) decision.
If RTA'd, the submitter must resubmit a complete submission — the 90-day review clock does not start until a complete submission is accepted.
Step 3 — Substantive review
Once accepted, FDA assigns the submission to a review team and begins substantive review:
- Evaluating substantial equivalence (intended use and technological characteristics)
- Reviewing performance testing data
- Assessing labelling
- Determining whether additional information is needed
Step 4 — Additional Information (AI) requests
If FDA needs more information, it issues an Additional Information (AI) request (formerly called "Interactive Review"). The submitter has a defined period to respond. The review clock typically pauses ("stops the clock") while awaiting the submitter's response.
Tips for AI requests:
- Respond completely and promptly — partial responses restart the clock
- Address each question individually and specifically
- Use a clear, question-by-question format
Step 5 — Decision
FDA issues one of three decisions:
| Decision | Meaning |
|---|---|
| SE (Substantially Equivalent) | Device is cleared; may be marketed |
| NSE (Not Substantially Equivalent) | Device is not cleared; consider De Novo or PMA |
| Withdrawal | Submitter voluntarily withdraws the 510(k) |
MDUFA VI performance goals
Under MDUFA VI (effective FY2023–FY2027), FDA commits to:
| Goal | Target |
|---|---|
| Total Time to Decision (TTD) — 510(k) | 90 calendar days |
| Substantive Interaction within | 60 calendar days |
| RTA review | 15 business days |
FDA publishes quarterly MDUFA performance reports on its website.