513(g) Request for Classification: When to Ask FDA Before Choosing Your Regulatory Pathway

The Most Expensive Regulatory Mistake Is Choosing the Wrong Pathway

Before you write a single line of your 510(k) or invest six figures into a PMA clinical study, there is a question you must be able to answer with confidence: how will FDA classify your device? For many novel, combination, or borderline-technology products, that answer is not obvious -- and assuming you know it is one of the fastest ways to burn your runway.

That is exactly where the 513(g) Request for Classification comes in. It is an underutilized, formally established mechanism under 21 CFR 807.85 and Section 513(g) of the Federal Food, Drug, and Cosmetic Act that allows manufacturers and developers to ask FDA directly how it would classify a device. Used strategically, it is one of the most cost-effective investments a device company can make early in its regulatory lifecycle.

What a 513(g) Request Actually Is

A 513(g) request is a formal submission to FDA asking the agency to identify the classification and regulatory controls that would apply to your device. Under 21 CFR 807.85, the agency is required to respond within 60 days of receiving the submission fee -- currently $6,493 for FY2024 (small businesses may qualify for a reduced fee).

The response you receive is not a clearance or approval. It is FDA's informed opinion on how your device would be classified and what pathway -- 510(k), De Novo, or PMA -- would likely apply. That distinction matters. A 513(g) response does not bind FDA in a future submission, but in practice, it provides substantial regulatory intelligence that can reshape your entire development and commercialization strategy.

When You Should Seriously Consider Filing a 513(g)

Not every device needs one. If you have a well-established predicate in a mature product category and your technology closely mirrors existing cleared devices, a 513(g) adds cost and time without proportional benefit. But there are specific scenarios where it is almost always worth it:

• Novel technology with no obvious predicate: If you are developing something genuinely new -- a first-in-class diagnostic algorithm, an implantable with a novel mechanism of action, or a combination device blending drug delivery with monitoring -- the classification landscape may be ambiguous. A 513(g) surfaces FDA's current thinking before you design your clinical or bench testing program around the wrong standard.
• Software as a Medical Device (SaMD) with unclear regulatory status: Following FDA's Digital Health Center of Excellence guidance and the Software as a Medical Device framework, many AI/ML-based tools sit in a gray zone between enforcement discretion and full 510(k) requirements. A 513(g) can provide clarity that internal legal and regulatory opinions simply cannot replicate.
• Devices that span multiple product codes: Some devices touch orthopedics, neurology, and software simultaneously. When your device does not fit neatly into a single FDA product code, a 513(g) helps you understand which center and division will own your submission and what the relevant special controls are.
• International devices entering the U.S. market: Companies with CE-marked or Health Canada-approved products frequently assume U.S. classification will mirror foreign frameworks. It often does not. A 513(g) anchors your U.S. regulatory strategy in FDA's actual classification framework, not an assumption.
• Pre-Series A or pre-submission planning: Sophisticated investors and strategic partners increasingly want to see regulatory pathway certainty before committing capital. A 513(g) response is a credible, FDA-sourced document you can include in due diligence packages.

How to Structure a Strong 513(g) Submission

FDA's guidance document 'De Novo Classification Process (Evaluation of Automatic Class III Designation)' and the agency's general submission standards inform how a 513(g) should be organized. Your submission should include a clear device description, intended use and indications for use, the proposed classification, and your rationale for that classification. You are essentially presenting your best argument to FDA and inviting their response.

Weak 513(g) submissions are vague, omit performance data that would help FDA understand the technology, or fail to address the most plausible alternative classifications. A strong submission anticipates the questions FDA is most likely to raise and answers them proactively. This is not a form you fill out -- it is a regulatory argument you construct.

What Comes After the FDA Response

Once you receive FDA's 513(g) response, you have actionable intelligence. If FDA signals a De Novo pathway, you can begin scoping your special controls proposal early. If they indicate a 510(k) is appropriate, you can prioritize predicate research. If the response suggests Class III with PMA requirements, you know to reassess your development timeline and investor conversations immediately.

Many companies follow a 513(g) with a Pre-Submission (Q-Sub) meeting under FDA's 'Requests for Feedback and Meetings for Medical Device Submissions: The Q-Submission Program' guidance, using the classification response as the foundation for a more detailed regulatory strategy dialogue.

The Strategic Value Is in the Certainty

A 513(g) request costs a few thousand dollars and 60 days. A misfiled 510(k) that FDA refuses to accept for review, or a De Novo submission built on the wrong classification framework, can cost six months and six figures. For device startups managing every dollar of runway, the calculus is straightforward.

At ADB Consulting and CRO Inc., Andre Butler and the team work with founders and regulatory affairs professionals to evaluate whether a 513(g) is the right first step, structure submissions that yield actionable FDA responses, and translate those responses into a regulatory roadmap built for your specific device and business stage.

If you are at a decision point on your regulatory pathway and are not completely certain which direction FDA would expect you to go, that uncertainty is worth resolving before it becomes expensive. Book a free discovery call with ADB Consulting and CRO Inc. at adbccro.com today and get expert eyes on your classification question before you commit to a pathway.