A K-number is public. The other isn't.

A 510(k) clearance ends in a K-number FDA publishes in its own database, and this blog reads that database every day. A device that clears with a laser inside it, or an X-ray tube, can also owe FDA a second filing under a different part of the law entirely — one FDA acknowledges with its own number, and never publishes anywhere.

What Part 1002 asks for

The Electronic Product Radiation Control provisions of the FD&C Act, implemented at 21 CFR Parts 1000 through 1050, regulate radiation-emitting electronic products — a category that reaches diagnostic X-ray systems, medical laser systems, and, until recently, ultrasonic therapy products — independently of whether the same product is also a medical device under 510(k) or PMA review. 21 CFR 1002.1 and its Table 1 set out, product category by product category, which manufacturers owe FDA an initial report before introducing the product into commerce, and which owe annual reports after that. Nothing in Part 1002 asks whether the product already has a K-number. The obligation runs on its own trigger, checked against its own table.

What CDRH sends back

FDA acknowledges a product report by assigning an accession number — commonly a seven-digit figure — in a letter confirming the filing was received. FDA has been explicit about what that acknowledgment is not: it does not mean FDA reviewed the report’s contents, approved the product, or confirmed the product meets the performance standard it reports against. The accession number is a receipt, not a verdict.

A number with no lookup

A K-number is built to be found. It lives in the openFDA 510(k) database, in FDA’s own device databases, and in this blog’s own monitored sources — a public, permanent, searchable record of what FDA cleared and when. An accession number has none of that. FDA describes accession numbers as proprietary information, known only to FDA and the manufacturer that filed the report — there is no public database, in this product or any other, where a second party can look one up. A competitor’s 510(k) history is a public record. A competitor’s radiation product report is not a record at all from the outside — it is a number two parties hold and nobody else can confirm.

The table itself moved

The set of products that owe a report is not fixed. A final rule FDA issued January 20, 2023, effective February 21, 2023, revised Table 1 directly: diagnostic X-ray systems — computed tomography, fluoroscopy, radiography — no longer require an initial or annual product report at all, and ultrasonic therapy products were removed from the reporting matrix entirely. Laser products stayed on the table. A firm that filed a product report for an X-ray system before 2023 and assumed the obligation was permanent is now carrying a filing the current rule doesn’t ask for.

The practice

A 510(k) or PMA clearance answers one question: can this device be marketed. It says nothing about whether the same device contains a radiation-emitting component that triggers its own filing under Part 1002 — that check runs against Table 1 directly, independent of the premarket pathway, whenever a laser or an X-ray source is part of the design. Per what we monitor and how often, FDA Radar reads the Federal Register, warning letters, recalls, 510(k) clearances, and the classification database — an accession number is not among them, and neither is any public tool’s. This is regulatory intelligence and method, never regulatory advice about whether a specific product’s radiation-emitting components trigger a report under Part 1002 — that determination belongs with your regulatory professional, checked against the current table, not last year’s.