513(g) vs. Pre-Submission: Which FDA Channel Fits the Question You're Actually Asking

Choosing the Wrong FDA Pathway Costs You Time You Do Not Have

One of the most consistent mistakes we see from early-stage device companies is treating the 513(g) and Pre-Submission (Pre-Sub) programs as interchangeable. They are not. Each tool is purpose-built for a different kind of question, and submitting the wrong one does not just slow you down -- it can send your regulatory strategy in the wrong direction entirely. This post breaks down exactly when to use each mechanism, what FDA expects from each, and how to avoid the costly mistake of conflating the two.

What a 513(g) Actually Does

A 513(g) request is governed by Section 513(g) of the Federal Food, Drug, and Cosmetic Act and implemented under 21 CFR Part 807. Its singular purpose is to obtain FDA's official determination of the regulatory classification of a device -- meaning, the agency will tell you whether your device falls under Class I, II, or III, and which, if any, predicate or regulation applies.

FDA's guidance document, 'FDA and Industry Procedures for Section 513(g) Requests for Information,' outlines the process clearly. You submit a description of your device, its intended use, and any relevant technological characteristics, and FDA responds -- typically within 60 calendar days -- with its classification determination and the applicable product code.

Use a 513(g) when your core question is: How does FDA classify this device? This is particularly valuable when:

• Your device sits at the intersection of two product codes and you need an authoritative classification opinion before committing to a submission pathway
• Your device uses a novel technology or material and there is no obvious predicate in the 510(k) database
• You are conducting investor due diligence and need documented regulatory status, not an internal assumption
• You are evaluating a product acquisition and need FDA's formal view on classification before closing

A 513(g) is not a strategy meeting. It does not invite FDA into a dialogue about your testing plan, your substantial equivalence argument, or your clinical study design. It is a formal, narrow inquiry into classification -- and FDA's response is exactly that.

What a Pre-Submission Is Actually For

The Pre-Submission program, described in FDA's guidance 'Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program' (most recently updated in 2023), is a collaborative mechanism that allows sponsors to engage FDA in substantive technical and regulatory dialogue before filing a formal submission.

Unlike the 513(g), a Pre-Sub is not about classification. It is about strategy, study design, and regulatory acceptability of your specific approach. FDA will provide written feedback -- typically within 70 calendar days for a written response request, or within 90 days if you request a meeting -- on questions such as:

• Whether your proposed substantial equivalence argument is likely to be defensible for a 510(k)
• Whether your bench testing protocol and acceptance criteria are adequate under the applicable special controls or performance standards
• Whether FDA agrees that a De Novo pathway is appropriate, and what the proposed special controls should include
• Whether your clinical study design, endpoints, and statistical plan are sufficient to support a PMA or De Novo
• How FDA interprets applicable guidance -- such as the 2023 Predetermined Change Control Plan guidance for AI/ML SaMD -- in the context of your specific product

The Pre-Sub is your opportunity to stress-test your strategy before you spend six to eighteen months executing it. Used well, it dramatically reduces the likelihood of a Refuse to Accept, a major deficiency letter, or an outright Not Substantially Equivalent determination.

Where Companies Get This Wrong

The most common error is submitting a Pre-Sub when the company has not yet resolved a fundamental classification question. If FDA's written response to your Pre-Sub has to begin by clarifying whether your device is even a Class II or Class III device, you have wasted a submission cycle and at least three months. Resolve classification first -- via a 513(g) if necessary -- then build your Pre-Sub around a well-defined device with a known regulatory home.

The second error is submitting a 513(g) and expecting strategic feedback. FDA's response will be narrow. Do not read a favorable classification opinion as implicit endorsement of your predicate, your testing approach, or your marketing claims. That work belongs in a Pre-Sub.

A Practical Decision Framework

Before you draft either submission, ask yourself one question: Do I know how FDA classifies this device?

• If the answer is no, or if you have meaningful uncertainty -- start with a 513(g).
• If the answer is yes, and your question is about how to get through the applicable pathway -- submit a Pre-Sub.
• If the answer is yes and your question is about whether a specific study design, predicate, or technical approach is acceptable -- submit a Pre-Sub.

In some cases, particularly for novel combination products or devices with dual-use claims, the right answer is a 513(g) followed by a Pre-Sub. These are not competing tools. They are sequential when the situation demands it.

Get the Sequencing Right Before You Submit Anything

At ADB Consulting and CRO Inc., we help device companies make these calls with precision -- not guesswork. Whether you are a founder preparing for your first FDA interaction or a VP of Regulatory evaluating a pipeline product, getting the front-end strategy right is the highest-leverage decision you will make in your regulatory process.

If you are unsure which mechanism fits your current question, or if you want an experienced set of eyes on a draft 513(g) or Pre-Sub before it goes to FDA, book a free discovery call with our team at adbccro.com. We will help you identify exactly what you are asking, which channel answers it, and how to structure your submission to get the most useful response FDA can give you.

For related guidance, see our Pre-Submission consulting program.