FDA Q-Submission (Pre-Sub) Guide: When and How to Use It

A Q-Submission (Q-Sub), commonly called a Pre-Submission (Pre-Sub), is a formal mechanism to get FDA feedback on specific questions before you file your 510(k). Used well, a Pre-Sub can resolve predicate disputes, confirm testing requirements, and prevent the AI requests that extend review timelines by months. Used poorly, it delays your program without providing useful guidance.

What a Q-Sub is — and isn't

A Q-Sub is a written package submitted to FDA requesting written feedback or a meeting. FDA commits to responding to written Q-Subs within 70 days and to meeting requests within 90 days. The response is written and becomes part of the administrative record for your device.

A Q-Sub is not a shortcut to clearance. FDA will not pre-clear your submission or give you advance assurance that your 510(k) will be cleared. What they will do is answer specific, well-framed questions about their expectations — which is often enough to avoid the most expensive surprises.

When a Pre-Sub is worth it

The time cost of a Pre-Sub (70-90 days) is only justified when the question is significant enough that getting it wrong would cost more time. Pre-Subs are most valuable when:

• Predicate selection is genuinely uncertain — your device could reasonably be compared to predicates in two different product codes, and the choice has major implications for testing
• Device classification is unclear — you're not sure whether your device is Class I, II, or III and the answer determines your entire regulatory pathway
• Novel technology raises unresolved questions — your device uses a technology (new material, AI algorithm, new sensing modality) for which there is no established 510(k) precedent
• Testing strategy is expensive and uncertain — you're facing clinical testing or expensive bench testing and want confirmation that the protocol and acceptance criteria are appropriate before you run the study
• Software level of concern is disputed — you believe your software is moderate level of concern, but features that might push it to major concern are present

When to skip the Pre-Sub

For straightforward devices with clear predicates, an established product code, and well-defined testing requirements, a Pre-Sub adds time without adding value. If you can find 10 recent 510(k) clearances in your product code with similar technological characteristics and clear test reports, you likely have enough information to file without FDA input.

Similarly, Pre-Subs on questions where FDA's written guidance already provides a clear answer are rarely productive — FDA will simply refer you to the guidance.

How to write good Pre-Sub questions

The quality of your Pre-Sub response is almost entirely determined by the quality of your questions. FDA answers the questions you ask — not the questions you should have asked. Guidelines for framing effective questions:

• Be specific — "Is K221234 an appropriate predicate for our device?" is answerable. "Do you agree with our regulatory strategy?" is not.
• Propose a position — "We propose to use ISO 11135 sterilization validation. Does FDA agree this is an appropriate standard for our sterilization method?" gives FDA something to confirm or correct.
• Number every question — FDA responds by number. Unnumbered or compound questions often get partial responses.
• Limit to 5-8 questions — Pre-Subs with 20+ questions receive less thorough responses. Focus on the questions that matter most.

Using the Pre-Sub response in your submission

FDA's written response to a Q-Sub is part of the administrative record and can be referenced in your 510(k). If FDA confirmed your predicate selection in a Pre-Sub, citing that confirmation in Section 2 of your submission strengthens your argument and signals to the reviewer that this question was already reviewed.

However, Pre-Sub responses are issued by the division at the time of the Pre-Sub. If significant time has passed, personnel has changed, or new guidance has been issued, FDA is not strictly bound by earlier Pre-Sub responses. Reference them, but don't treat them as ironclad guarantees.