FDA
Warning Letter
Fifteen business days to answer,
and it is public from day one.
A Warning Letter names the requirements FDA believes you have violated and asks for documented proof of correction. Batch Assessment reads every citation in the letter against the quality records you already hold, and returns, requirement by requirement, what the evidence shows, where it sits, and what is still missing.
A Warning Letter is not a fine, and not an order.
It is FDA saying the next move is yours.
It starts with an inspection. At the close, the investigator may hand over a Form 483, a list of what they observed. FDA then classifies the inspection: No Action Indicated, Voluntary Action Indicated, or Official Action Indicated. It is the last of those, OAI, that can become a Warning Letter, usually weeks or months later, after the agency has reviewed both the observations and whatever the firm sent back.
The letter names the requirements FDA believes were violated, cited to the regulation. For a device manufacturer that is typically 21 CFR Part 820: design controls under 820.30, complaint handling under 820.198, corrective and preventive action under 820.100, purchasing controls under 820.50. It will normally state that the devices are adulterated within the meaning of the Act because the methods used in their manufacture do not conform to those requirements.
In FDA's own framing the letter is advisory. It does not itself impose a penalty, and it does not commit the agency to enforcement. What it does is establish, on the record and in public, that FDA told you.
That last part matters more than most of the rest. Warning Letters are posted to a searchable database on FDA's website. Customers read them. So do competitors, hospital procurement teams, notified bodies, investors and acquirers.
Fifteen business days.
The letter asks the firm to notify FDA in writing, within fifteen business days of receipt, of the specific steps it has taken to address each violation, with documentation of the corrections and corrective actions. Where a correction cannot be completed in that window, the firm is expected to explain the reason and give the timetable.
So the response is not a letter of intent. It is an evidence package: for every citation, the root cause, what was changed, what proves the change happened, and where that proof lives. FDA has seen the firm's paperwork once already. A response that restates good intentions without records attached tends to produce a second inspection rather than a close-out.
Fifteen business days is three calendar weeks. Most of that time, at most firms, goes not into deciding what is right but into locating the record that supports each answer and citing where it came from.
Form 483 and Warning Letter are not the same document.
They are often spoken about together, and the difference is worth being precise about, because the second one carries consequences the first does not.
| Form 483 | Warning Letter |
|---|---|
| Handed over at the end of an inspection | Sent weeks or months later, after agency review |
| One investigator's observations | The agency's position on the violations |
| Not published by FDA as a matter of course | Posted publicly in a searchable database |
| A response is expected, and is your chance to prevent escalation | A written response is required within fifteen business days |
| Does not on its own affect approvals or exports | Can hold up Class III approvals and export certificates |
What it costs, before anyone is fined.
The letter itself carries no penalty. The consequences attached to it are what bite. FDA states in the letter that failure to address the violations may result in seizure, injunction and civil money penalties, and that action may be taken without further notice. Beyond that: requests for Certificates to Foreign Governments may not be granted, which stalls export markets. Class III premarket approval applications tied to the cited violations will not be approved until those violations are addressed. Unresolved violations may prevent other federal agencies from awarding contracts.
Then there is the part FDA does not administer. Philips shares fell around 8% on a device Warning Letter; Medtronic's fell more than 9% after one went to its diabetes business. Distributors and hospital systems ask questions, and some of them pause orders while they wait for answers. Insurers, lenders and acquirers add it to diligence. One published estimate puts the annual cost to the US device industry of 483s, Warning Letters and consent decrees at 2.5 to 5 billion dollars, with another 1 to 2 billion in lost sales.
None of that is triggered by the violation. It is triggered by the letter becoming public before the firm can show its side.
What a response has to do, citation by citation.
- 1
Read each citation as a question about evidence
Every cited clause asks the same thing: show the records that demonstrate you meet this requirement. Start by turning the letter into a list of those questions.
- 2
Find the records that answer it
Quality manual, procedures, validation protocols, design history files, complaint records, CAPA logs, training records, supplier files. The answer is usually already written down somewhere.
- 3
Judge honestly whether they answer it
Evidenced, partly evidenced, or not evidenced. A response that overstates one item damages the credibility of the rest of the package.
- 4
Cite where the proof sits
Document name, version, section. FDA is verifying, not taking your word for it, and a reviewer who cannot find the proof treats it as absent.
- 5
Name the gaps and commit to dates
Where evidence genuinely does not exist yet, say so and give the timetable. That is a far better position than a claim the follow-up inspection disproves.
For each citation in the letter, the evidence, the source, and the gap.
| Item | Output |
|---|---|
| Citation | The cited clause, e.g. 21 CFR 820.100(a), as written in the letter |
| Judgment | Evidenced / Partly evidenced / Not evidenced / Out of scope |
| Reasoning | Why the records support, or fail to support, that requirement |
| Source | Document name, version and the exact section relied on |
| Missing evidence | What a reviewer would still need to see before this citation closes |
| Review points | Items a person must check before anything is sent to FDA |
Why this, and not a general-purpose AI.
A general assistant will summarize a Warning Letter well. That is not the work. The work is going clause by clause through documents you already hold and saying, for each one, what is there, where it is, and what is missing, in a form a reviewer can check.
Batch Assessment is built for that shape of task: a fixed list of items, answered against registered internal documents, with the reasoning and the source kept attached to every line.
The AI produces the first pass. The people who sign the response decide what it says.
Nothing here goes to FDA unread.
The output is a working draft for the quality and regulatory teams, not a submission. Every line carries its reasoning and its source so a reviewer can agree, correct, or reject it, and the items the AI could not evidence are flagged rather than smoothed over.
That is the point of doing it this way. A response is only as good as the records behind it, and the fastest way to lose a close-out is to assert something the follow-up inspection contradicts.
記録はある。
探すのに時間がかかる。 The records exist.
Finding them is slow.
15営業日では、探している時間はありません。Fifteen business days is not enough time to go looking.
Frequently asked questions
Device Warning Letters generally require a written response within fifteen business days of receipt. A small number of recent letters have granted thirty. Read the deadline off your own letter rather than assuming, and note that the clock runs from receipt, not from the date on the page.
No. It carries no penalty by itself and FDA describes it as advisory. What it does is put on public record that the agency has told you, which is the precondition for seizure, injunction, civil money penalties or a consent decree if the violations are not corrected.
Not taken down, but closed out. FDA issues a close-out letter after it has evaluated and verified the corrective actions, usually by follow-up inspection. The original letter stays in the public database with the close-out recorded against it. Violations that are not correctable by their nature do not get a close-out at all.
A line per citation: a first-pass judgment, the reasoning behind it, the document and exact section relied on, and anything still missing. Your team reviews it, supplies what is absent, and writes the response.
No. Register the quality records you already hold, in the formats they are already in, and the AI agent reads across them. The premise of the product is that the evidence usually exists and the work is connecting it to the requirement.