FDA Inspections & Warning Letters
FDA's direct inspection authority over device manufacturers (domestic and foreign) — and the warning letter system — are distinctly US mechanisms. FDA can inspect without advance notice (announced or unannounced).
Types of FDA device inspections
| Inspection type | Description |
|---|---|
| Surveillance inspection | Routine inspection of registered establishment; periodic (typically every 2 years for Class II/III) |
| Compliance follow-up | After a previous inspection with observations — checks for corrective actions |
| Pre-approval inspection (PAI) | Before FDA approves a PMA; verifies manufacturing processes and data integrity |
| For-cause inspection | Triggered by complaints, MDR trends, or recall activities |
| Unannounced inspection | FDA investigators may arrive without advance notice for domestic manufacturers |
What FDA investigators examine
- QMSR compliance — design controls, CAPA, complaint handling, MDR procedures
- Document and record integrity — are records complete, accurate, and retrievable?
- Manufacturing practices — cleanliness, controlled processes, calibration, environmental monitoring
- Complaint files — are complaints reviewed for MDR reportability?
- Corrective actions — response to previous observations
FDA Form 483 — Inspectional Observations
At the end of an inspection, the FDA investigator may issue FDA Form 483 — a list of observed conditions that may constitute violations. A 483 is not a final determination of violation — it is an observation that the manufacturer must respond to.
Response to 483: Respond in writing within 15 business days from receipt of the 483. Request an extension in writing before the deadline expires if complex issues require longer resolution timelines. FDA will generally grant reasonable extensions if requested and justified.
Official resources
The FDA investigator typically provides an oral briefing at the conclusion of the inspection and issues the written 483 within a few days. Manufacturers should not assume no 483 will be issued until the written document is received.