FDA 510(k) Substantial Equivalence Guidance

01 What the document says

This guidance explains the decision process FDA uses to determine substantial equivalence in a 510(k). It follows the 510(k) decision-making flowchart step by step: is there a legally marketed predicate; does the new device have the same intended use; does it have the same technological characteristics, and if not, do the differences raise different questions of safety and effectiveness; and does the performance data show the new device is as safe and effective as the predicate. It also addresses the choice of predicate, the use of multiple or split predicates, and reference devices.

For IVDs, intended use includes the analyte, specimen type, the clinical indication, the intended user, and the use setting, so a change in any of those can shift the comparison. Technological characteristics include the detection principle, reagents, and instrument platform. Differences in these areas are common for IVDs and are resolved with analytical and clinical performance data rather than being disqualifying in themselves.

The guidance describes what a 510(k) should contain to support each decision point, including the 510(k) Summary or Statement, the substantial equivalence comparison, and the performance data section. It also notes that FDA may ask for clinical data when analytical data or bench testing alone cannot resolve a difference. Special and Abbreviated 510(k) pathways and specific device-type guidances sit alongside this document rather than being covered by it.

02 What it means when you plan a study

• Choose the predicate before designing the study; the predicate's cleared intended use, specimen types, and performance establish what the new device must match, and the comparator in your clinical study is often the predicate itself or the reference method the predicate was cleared against.
• Every element of your intended-use statement (specimen type, population, user, setting) should be represented in the clinical data; adding a specimen type or user group after the study typically means more enrollment.
• Different technological characteristics generally mean more performance data, not a different pathway, so budget for the analytical studies that address each difference in addition to the clinical comparison.
• When the predicate was cleared with performance against a reference method, your labeling will be compared on the same terms; a study that only shows agreement with the predicate may fall short of reviewer expectations for the claim.
• If no predicate exists, the submission is not a 510(k); De Novo planning changes the study design, so settle the pathway question early through a Pre-Submission.

03 Pathways it applies to

• 510(k) Clinical Studies
• Dual Submission Studies

Source document: The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)] (fda.gov).