FDA · guide

How to Read a 510(k) Clearance Letter and Track Competitor Clearances

Updated September 1, 2026

What a 510(k) number tells you

Every premarket notification receives a K-number: the letter K, two digits for the year the submission was received, and a four-digit sequence. For example, K251628 was received on October 9, 2025 and cleared with a letter that uses the number as its subject line (example clearance letter K251628). Because the sequence increments through the year, the number alone gives a rough sense of when a competitor filed.

Anatomy of the clearance letter

FDA's substantial equivalence letters follow a fixed header. Using K251628 as the model, the top of the letter states:

The body then states that FDA has 'determined the device is substantially equivalent (for the indications for use stated in the enclosure)' to a legally marketed predicate. That parenthetical is the most important phrase in the letter: the clearance covers only the indications on the attached form, not everything the device could do.

Form FDA 3881, Indications for Use

The enclosure is Form FDA 3881. It records the 510(k) number, the device name, the indications for use text and the type of use, marked as prescription use under 21 CFR 801 Subpart D or over-the-counter use under 21 CFR 801 Subpart C (example letter, Form FDA 3881 page). FDA's electronic submission template explains that the form captures the disease or condition the device will diagnose, treat, prevent, cure or mitigate, including the patient population (eSTAR 510(k) template). When comparing competitors, compare the 3881 text word for word; small differences in population or setting are often the whole story.

510(k) summary versus 510(k) statement

Every 510(k) must include one of two disclosure vehicles. A 510(k) summary under 21 CFR 807.92 names the predicate, describes the device and its intended use, compares technological characteristics, and summarizes nonclinical and clinical testing; it is published with the letter. A 510(k) statement under 21 CFR 807.93 is instead a certification that the submitter 'will make available all information included in this premarket notification on safety and effectiveness within 30 days of request by any person'. The database records which one was used in a field that 'contains either SUMMARY or STATEMENT' (release file layout). If a competitor filed a statement, you can request the redacted safety and effectiveness information directly from them.

Decision codes and flags

The releasable 510(k) files carry a decision code rather than plain text. Substantially equivalent outcomes include SE, SN (equivalent for some indications), SU (with limitations), ST (subject to tracking) and SP (postmarket surveillance required); not-substantially-equivalent outcomes include NE and UD; WD marks a withdrawal. The files also flag the submission type (Traditional, Special or Abbreviated), whether a Third Party reviewed it, and whether expedited review was granted (release file layout). A run of Special 510(k)s from one applicant usually signals iterative changes to an existing product.

The 510(k) database and its refresh cycle

The releasable 510(k) database can be searched by 510(k) number, applicant, device name or product code, and summaries are available through the web interface for more recent records (Medical Device Databases). FDA's database index describes it as updated once a week, while the TPLC data-source page and the openFDA 510(k) endpoint describe monthly refreshes (TPLC data sources; openFDA device 510(k)). In practice, check the 'content current as of' date on the page you are using. Note also that the database is not updated when a 510(k) changes hands, so the applicant name may not be the current owner.

The 510(k) release files

For bulk work, FDA publishes zipped files of releasable 510(k)s for specific time periods, with a documented layout covering applicant, address, date received, decision date, decision code, review advisory committee, product code, summary-or-statement flag, third party flag, expedited review flag and device name (Downloadable 510(k) files). Loading the current-year file into a spreadsheet and filtering on your product codes is the simplest competitor scan.

Setting up competitor monitoring

1. Build a product-code list from the Product Classification database and from the header of each competitor's most recent letter.
2. Build an applicant list, including subsidiaries and former names, since applicant is the sponsor named at filing.
3. Query openFDA on a schedule. The device 510(k) endpoint exposes applicant, product_code, decision_date, decision_code, k_number, device_name, third_party_flag and statement_or_summary as searchable fields (openFDA searchable fields). Using the documented query syntax, a product-code watch for the current year looks like https://api.fda.gov/device/510k.json?search=product_code:LRK+AND+decision_date:[20260101+TO+20261231]&limit=100, and https://api.fda.gov/device/510k.json?search=product_code:LRK&count=applicant.exact ranks applicants.
4. For each new K-number, open the letter PDF, read the 3881 indications, and file the summary.
5. Watch the Third Party flag. About half of all 510(k)s are eligible for the Third Party Review Program, in which an accredited review organization reviews the submission first and FDA's decision timeframe is within 30 days of receiving its recommendation, with no separate FDA user fee (510(k) Third Party Review Program); competitors using it may clear faster than the standard clock suggests.

RegPing's FDA bot delivers new 510(k) clearance notices into Discord filtered by product code or applicant, so the weekly check becomes an alert.

Where to verify

• Example 510(k) clearance letter and Form FDA 3881 (K251628)
• 21 CFR 807.92 content of a 510(k) summary
• 21 CFR 807.93 content of a 510(k) statement
• File layout for releasable 510(k)s
• Downloadable 510(k) files
• openFDA device 510(k) endpoint
• 510(k) Third Party Review Program

This guide is general information, not legal advice. Verify against the primary source and consult counsel before acting.