What Is a 513(g) Request and When Should I Use One?

Device classification determines everything downstream: which premarket pathway applies, what the applicable special controls require, and what a predicate comparison needs to show. Most manufacturers identify their classification confidently using FDA's own product classification database. A 513(g) exists for the cases where that confidence is not justified, and guessing wrong costs far more time than the request itself.

What a 513(g) Request Actually Is

Section 513(g) of the FD&C Act lets any person submit a written request asking FDA to state in writing how a particular device is classified and what requirements apply to it. FDA's response is a formal agency position, not a courtesy opinion; it carries real weight in a later submission, since a reviewer evaluating a 510(k) or De Novo will expect the submission to be consistent with the 513(g) determination FDA already issued for that device. What a 513(g) is not: it does not authorize marketing, it does not substitute for a 510(k), De Novo, or PMA, and it does not evaluate safety or effectiveness data.

The Fee and the 60 Day Statutory Response

A formal 513(g) submitted to FDA carries a user fee, set annually and published on FDA's fee schedule, in addition to any preparation cost. FDA's statutory target is a written response within 60 calendar days of receipt, though the agency's actual response time runs 60 to 90 days in practice depending on workload and whether the request requires internal consultation across review divisions. A Classification Determination Memo, which reaches a written classification opinion without filing anything with FDA, is a faster alternative when the goal is internal clarity rather than an FDA position on the record; it is typically delivered within days rather than months.

When a 513(g) Beats Guessing Your Own Classification

A handful of situations make a 513(g), or at minimum a documented internal classification memo, clearly worth the cost over guessing:

• No obvious predicate exists. If a search of FDA's 510(k) database and product classification database returns nothing clearly matching the device's intended use, guessing a product code invites an acceptance-stage rejection months later.
• The device could fall under more than one product code. Devices that combine functions, or that sit at the boundary between two established categories, often have a real argument for either classification, and the choice has direct consequences for testing burden and pathway.
• Software or AI/ML components create a gray zone. A device whose primary function is software-driven, or that incorporates adaptive algorithms, frequently falls outside the classification regulations written before that technology existed.
• International devices entering the US market for the first time. A device cleared or approved in another jurisdiction has no guarantee its FDA classification matches its classification abroad; confirming before investing in a full submission avoids a costly mismatch.

When a 513(g) Is Unnecessary

A 513(g) adds cost and, for the formal FDA-filed version, adds 60 or more days to a project timeline. Skip it when the device matches an existing, well established product code with multiple cleared predicates sharing the same intended use and technology; in that situation, the classification is already settled by precedent, and a 513(g) confirms what is already known rather than resolving real uncertainty.

How a 513(g) Differs From a Pre-Submission, and When to Use Both

A 513(g) answers a narrower question than a Pre-Submission: what is this device's classification and pathway. A Pre-Submission meeting comes after that question is settled, and addresses whether FDA agrees with the specific predicate, testing plan, or technical approach within the chosen pathway. Many sponsors use both in sequence: a 513(g) to confirm the pathway, then a Pre-Sub to confirm the strategy within it. For a fuller side by side comparison of 513(g), Pre-Sub, and 510(k) timelines and use cases, see our 513(g) vs Pre-Sub vs 510(k) comparison.

ADB's regulatory team prepares 513(g) requests and Classification Determination Memos to resolve exactly this kind of classification uncertainty as part of the 513(g) Classification Request service.

Frequently Asked Questions

Is a 513(g) request the same as FDA clearing my device?

No. A 513(g) is FDA's written opinion on classification and applicable pathway only. It does not clear, approve, or authorize marketing of the device. A separate 510(k), De Novo, or PMA submission is still required afterward.

How long does FDA take to respond to a 513(g) request?

FDA's statutory target is 60 calendar days from receipt, though the agency's actual response time often runs 60 to 90 days in practice. An ADB-prepared Classification Determination Memo, which reaches a written opinion without an FDA filing, is typically delivered within days.

Should I file a 513(g) or request a Pre-Submission meeting?

File a 513(g) when the open question is which classification regulation and pathway apply. Request a Pre-Submission when the pathway is already known and the open question is whether FDA agrees with a specific predicate, testing plan, or technical approach. Many sponsors use both in sequence.