A preamendment device is one that was labeled, promoted and distributed in US interstate commerce for a specific intended use before May 28, 1976. If your firm owned it then, has not significantly changed it, and FDA requires no PMA for its type, it needs no 510(k), and FDA can confirm its status.
Key takeaways
- May 28, 1976 is the effective date of the Medical Device Amendments. Devices your firm legally marketed in the US before that date, and has not significantly changed, are "grandfathered".
- FDA's rule is that you "must be the owner of the device on the market before May 28, 1976". A similar device first sold after that date needs its own 510(k).
- FDA accepts dated records, notarized affidavits, or a mix of both as proof. You can ask CDRH for an official determination with Form FDA 3752.
- FDA's classification database lists 86 product codes as unclassified preamendment types. 66 of them are 510(k) types, and 13 are on FDA's June 2026 list of types it intends to exempt.
- We measured how often FDA clears unclassified device types: 202 510(k)s from 2023 to 2025, about 2% of all clearances each year.
This guide is part of our 510(k) hub. If you are not sure your device needs a 510(k) at all, start with the free pathway finder.
What is a preamendment device?
A preamendment device is a device that was in US interstate commerce, labeled and promoted for a specific intended use, before May 28, 1976 [2]. That date is the effective date of the Medical Device Amendments to the Federal Food, Drug, and Cosmetic Act (FD&C Act) [3].
After that date, a new device needs FDA marketing authorization. For most moderate-risk devices that means a 510(k), unless the device is exempt; novel or high-risk devices need a De Novo or a PMA [3]. You file a 510(k) at least 90 days before you plan to sell, and you may not market the device until FDA clears it [3, 4].
FDA calls preamendment devices "grandfathered" [3]. You will also see the spellings "pre-amendment" and "preamendments". They mean the same thing.
Two kinds of early distribution do not count. Devices distributed solely for research or investigational use were not in interstate commerce for this purpose. Neither were plant-to-plant transfers inside the same company [1, 2].
Does a preamendment device need a 510(k)?
No, if three conditions all hold. First, the device has not been significantly changed since May 28, 1976. Second, it keeps the same intended use. Third, FDA has not published a regulation that requires a premarket approval (PMA) application for it [3].
Each condition can fail on its own:
- A significant change. Under 21 CFR 807.81(a)(3), you must file a 510(k) before a change that could significantly affect safety or effectiveness. Examples are a change in design, material, chemical composition, energy source or manufacturing process [4].
- A new intended use. If you label the device for a different intended use, FDA treats it as a new device that needs a 510(k) [3].
- A PMA requirement. If FDA has published a regulation requiring PMAs for the device type, the device no longer qualifies [3].
A real example shows what happens after a change. On June 12, 2025, FDA cleared a Special 510(k) from Davol for Bard Mesh, a surgical mesh on the market as a preamendment device since 1962. Davol filed it to clear changes made since then, and named its own preamendment device as the predicate [9].
Preamendment status is about the 510(k) only. You still register your establishment and list the device under 21 CFR 807.20 [4]. You also follow the rules on labeling (21 CFR part 801), the Quality Management System Regulation (21 CFR part 820) and adverse event reporting (21 CFR part 803).
Who can claim preamendment status?
FDA's 510(k) page puts it this way: "you must be the owner of the device on the market before May 28, 1976, for the device to be grandfathered" [3]. It goes on: if your device is similar to a grandfathered device but was marketed after that date, it is not grandfathered, and you must submit a 510(k) [3].
So a manufacturer that makes the same type of product today, even an identical copy, cannot use another firm's status. It can, however, cite the preamendment device as a predicate in its own 510(k).
There is one narrow exception. Under 21 CFR 807.85(b), two kinds of firms need no 510(k) if the device was in commercial distribution before May 28, 1976 [4]. One is a distributor that sells the device under its own name. The other is a repackager that adds its own name and changes nothing else.
How do you prove preamendment status to FDA?
You keep documents showing that the device was in interstate commerce, and labeled and promoted for a specific intended use, before May 28, 1976 [1, 2]. FDA accepts three methods:
| Method | When to use it | What you provide |
|---|---|---|
| A. Direct proof | You still have dated records | Dated advertisements, catalog pages, promotional material, journal articles, manufacturing documents, and shipping documents such as invoices, receipts and bills of lading |
| B. Affidavits | You have none of the records in method A | A notarized affidavit from a current or former employee or company director who knew the device's labeling and promotion, plus one from a credible person who used the device before May 28, 1976. If you cannot get the employee affidavit, provide an affidavit describing your efforts, plus affidavits from two credible users |
| C. Available information | You have only part of the records | All the records you have, plus as complete an affidavit as possible from an employee and from a user |
Whatever the method, the full set of documents must prove two things [1, 2]. First, the device was in interstate commerce before May 28, 1976. Second, the documents must show the specific intended use the device was labeled and promoted for.
The details matter [1, 2]:
- Send copies, not references. If you rely on a journal article, include a copy of it.
- Use machine-printed dates. Form FDA 3752 says: "Handwritten dates are generally used only in manufacturing and shipping documents; in other instances dates should be machine printed and original."
- Exclude research use. No document should show the device was used in a research study or under investigational use before May 28, 1976.
- State financial interest. Every affiant must state their financial interest in the device or the firm.
- Notarize every affidavit. The employee affidavit must also explain why invoices or shipping records are not available.
- Match the intended use. If you will cite the device in a 510(k), the intended use you document should match the one you propose for the new device [2].
How do you submit a preamendment determination request?
If you want FDA's official view, you may submit Form FDA 3752, "Pre-Amendment Device Determination Request", with your documents [1, 2]. The steps:
- Identify the device. Give the last known manufacturer, the brand names and the earliest known date of interstate commerce.
- State your purpose. The form offers three: to use the device as a 510(k) predicate, to document status for a device listing, or to document status for customers and FDA staff.
- Choose method A, B or C and attach the documents for it.
- Sign the certification that the information is truthful and accurate.
- Send it to CDRH. The form, dated April 2013, gives a mailing address at CDRH's Office of Compliance, which FDA has since merged into its Office of Product Evaluation and Quality [11]. FDA's current page names Device Determinations as the contact, at DeviceDetermination@fda.hhs.gov. Email them first to confirm where to send it.
After you submit, FDA assigns a tracking number and sends an acknowledgment of receipt [1]. A reviewer then issues an official determination. Form FDA 3752 says the determination letter is mailed to you and posted on FDA's website. If documents are missing or the form is incomplete, FDA sends a deficiency letter instead [1].
The form states no review time, and we found no published FDA target for these requests.
What are unclassified preamendment device types?
An unclassified device is a preamendment device type that the original classification panels never classified, so no classification regulation exists for it [6]. FDA can still classify these types later, through a panel recommendation, a proposed rule and a final rule [6].
Unclassified is not the same as exempt. FDA's classification database lists 86 product codes as unclassified, every one marked as preamendment [7]. They fall into three groups:
| Group | Product codes | What it means for a new device |
|---|---|---|
| 510(k) types | 66 | A new device needs a 510(k), compared with a legally marketed predicate |
| On FDA's June 2026 intent-to-exempt list | 13 | FDA does not expect 510(k)s for now [5] |
| Blood donor screening tests and blood grouping reagents | 7 | Not 510(k) types. FDA's database says "Contact ODE", and most point to biologics rules in 21 CFR parts 610 and 660 |
Our analysis of openFDA data shows how often new devices of these types are cleared [8]:
| Year | 510(k)s cleared for unclassified device types | Share of all 510(k) clearances |
|---|---|---|
| 2023 | 66 | 2.0% |
| 2024 | 75 | 2.4% |
| 2025 | 61 | 1.9% |
Those 202 clearances span 30 product codes, and 82 of them came from applicants outside the US [8]. The six most common types:
| Product code | FDA device name | 510(k)s cleared, 2023 to 2025 |
|---|---|---|
| FRO | Dressing, Wound, Drug | 53 |
| KGN | Wound Dressing With Animal-Derived Material(s) | 32 |
| MQC | Mouthguard, Prescription | 18 |
| MRW | System, Facet Screw Spinal Device | 17 |
| QSY | Hemostatic Wound Dressing Without Thrombin or Other Biologics | 13 |
| LFL | Instrument, Ultrasonic Surgical | 10 |
Some unclassified types are moving toward exemption. On June 5, 2026, FDA updated its guidance on unclassified devices it intends to exempt from the 510(k), adding five types [5]. The guidance now lists 13 product codes, such as hearing protectors (EWD, EWE), alcohol pads (LKB) and eye cups (LXQ). Until the exemption happens, FDA does not intend to enforce the 510(k) requirement for them, unless it learns new information [5]. The policy does not cover combination products, such as products containing an antimicrobial agent. Registration, listing, labeling, the Quality Management System Regulation and Medical Device Reporting still apply [5].
Your product code tells you which group you are in. Complizen's Device Classification tool returns the class and product code that fit your device description. With the code in hand, FDA's classification database shows whether the type is unclassified.
How we counted. We used the device class openFDA lists for each product code today, which may differ from its class on the decision date [8].
How do 510(k)s use preamendment devices as predicates?
A preamendment device is a valid predicate. Under 21 CFR 807.92(a)(3), a legally marketed device you can compare against includes a device legally marketed before May 28, 1976 [4]. FDA's 510(k) page notes that recently cleared devices are often selected as the predicate [3].
We searched the public 510(k) summaries for the devices FDA cleared in 2025, 3,185 distinct documents in all [9]. 25 use the word "preamendment" or "pre-amendment":
| How the summary uses it | Summaries |
|---|---|
| In the classification line, for example "Unclassified, Pre-Amendment" | 13 |
| As the root of the predicate chain, for example predicates "determined by FDA to be substantially equivalent to pre-amendment devices" | 9 |
| Other uses, such as citing the company's own preamendment device as the predicate | 3 |
Even for unclassified types, most summaries do not use the word. Of the 61 clearances for unclassified types in 2025, 12 did [8, 9].
If you plan to cite a preamendment device directly, you need its status documented. That is what the "510(k) predicate" purpose on Form FDA 3752 is for [1].
What gaps weaken a preamendment claim?
Common gaps to check before you rely on the claim:
- Claiming another firm's status. FDA ties grandfathering to the owner of the device on the market before May 28, 1976 [3].
- Relying on sales outside the US. The proof must show US interstate commerce. Sales only within other countries do not count [12].
- Undated or handwritten-dated records. Outside manufacturing and shipping documents, dates should be machine-printed and original [1].
- Records that show research use. Devices distributed solely for research or investigational use were not in interstate commerce for this purpose [1, 2].
- A drifted intended use. If today's labeling claims a different intended use than the 1976 labeling did, you have a new device [3].
- Quiet design changes. A new material, energy source or manufacturing process can trigger 21 CFR 807.81(a)(3) [4]. Our guide on when a device modification needs a new 510(k) explains how to assess a change.
What should manufacturers outside the US know?
A firm outside the US can qualify, but only for a device it shipped into the US before May 28, 1976. The FD&C Act defines interstate commerce to include commerce between any state and any place outside it [12]. What counts is US commerce under your firm's ownership, not sales in your home market [2, 3].
Affidavits from people living outside the US "may be taken into consideration", FDA says, when they come with affidavits signed by people living in the US [2].
For most international manufacturers, the practical path is a 510(k) that uses a recent cleared predicate. If your device type is unclassified, check whether it is on FDA's June 2026 intent-to-exempt list before you plan a submission [5]. If it is on that list, you still need establishment registration and device listing before commercial distribution. If you are outside the US, you also need a US Agent (21 CFR 807.40) [4]. The annual registration fee is $13,785 from October 1, 2026 [10]. Our guide to whether your device needs FDA approval, clearance or an exemption covers how to check.
If your preamendment claim looks weak, a 510(k) is the likely route. Complizen's free gap assessment checks your device documents against what a 510(k) needs, so you know what a submission takes before you decide.
Frequently asked questions
What does preamendment mean for a medical device?
It means the device was distributed in US interstate commerce, labeled and promoted for a specific intended use, before May 28, 1976. That is the effective date of the Medical Device Amendments. If your firm owned it then and has not significantly changed it, it usually needs no 510(k).
What is a grandfathered medical device?
A grandfathered device is FDA's informal name for a preamendment device that still qualifies. It was legally marketed in the US before May 28, 1976, has not been significantly changed, and keeps the same intended use. FDA has also not required a PMA for its type.
Can I claim preamendment status for a copy of an old device?
No. FDA says you must be the owner of the device that was on the market before May 28, 1976. A similar or identical device first marketed after that date needs its own 510(k), though it may use the preamendment device as a predicate.
What documents prove preamendment status?
Dated records from before May 28, 1976 work best: advertisements, catalog pages, promotional material, journal articles, manufacturing documents and shipping records such as invoices. Together they must show US interstate commerce and the specific intended use. Notarized affidavits can fill gaps.
What is Form FDA 3752?
Form FDA 3752 is the Pre-Amendment Device Determination Request. You may use it to send CDRH your evidence and ask for an official determination. It asks for the device details, your purpose, your documentation method (A, B or C) and a signed certification.
How long does a preamendment determination take?
We found no published FDA target time, and the form gives none. After you submit, FDA sends an acknowledgment with a tracking number. A reviewer then issues a determination letter, or a deficiency letter if documents are missing or the form is incomplete.
Can affidavits replace documents?
Yes, if you have no records. Method B accepts a notarized affidavit from a current or former employee who knew the labeling and promotion, plus one from a credible user. Each must state the affiant's financial interest. Method C combines partial records with affidavits.
Do affidavits from outside the US count?
Only alongside US affidavits. FDA says affidavits from people residing in other countries may be taken into consideration when accompanied by affidavits signed by people residing in the US. The evidence must still show US interstate commerce before May 28, 1976.
What is an unclassified medical device?
An unclassified device is a preamendment device type that the original panels never classified, so no classification regulation exists. FDA's database lists 86 such product codes. Most are 510(k) types, so a new device of that type still needs a 510(k).
Do unclassified devices need a 510(k)?
Usually yes. 66 of the 86 unclassified codes are 510(k) types, and FDA cleared 202 such 510(k)s from 2023 to 2025. For 13 codes on FDA's June 2026 intent-to-exempt list, FDA does not expect 510(k)s for now, except for combination products.
Can a preamendment device be a 510(k) predicate?
Yes. Under 21 CFR 807.92(a)(3), a device legally marketed before May 28, 1976 is a legally marketed predicate. FDA notes that recently cleared devices are often chosen as predicates instead. In 2025, 9 summaries described their predicates as equivalent to preamendment devices.
Does a preamendment device still need registration and listing?
Yes. Preamendment status removes only the 510(k) requirement. You still register your establishment, list the device, and follow labeling, quality management system and adverse event reporting rules. Foreign establishments also need a US Agent before commercial distribution. The FY2027 registration fee is $13,785.
References
- FDA. Form FDA 3752, Pre-Amendment Device Determination Request. Form dated April 2013.
- FDA. Preamendment Status. Content current as of November 15, 2017.
- FDA. Premarket Notification 510(k), sections "When a 510(k) is Required" and "Preamendment Devices". Content current as of August 22, 2024.
- 21 CFR 807.3(b), 807.20, 807.40, 807.81, 807.85, 807.92 and 807.100. Text checked in the April 1, 2025 annual edition on govinfo.
- FDA. Intent to Exempt Certain Unclassified Medical Devices from Premarket Notification Requirements. Guidance issued June 5, 2026.
- FDA. Device Classification, FDA presentation for the advisory panel meeting of November 7, 2023 on blood irradiators, including "What is an Unclassified Device?".
- openFDA. Device classification API, product codes with device class "U" (unclassified), with submission type and unclassified reason. Data last updated October 12, 2026; accessed October 24, 2026.
- openFDA. 510(k) API, substantially equivalent decisions dated January 1, 2023 to December 31, 2025, with device class "U". Analyzed by Complizen, accessed October 24, 2026.
- FDA. 510(k) Premarket Notification database, public 510(k) summaries for 2025 clearances, including K251557. Searched by Complizen for "preamendment" and "pre-amendment", accessed October 24, 2026.
- FDA. Medical Device User Fee Rates for Fiscal Year 2027. Federal Register, July 30, 2026.
- FDA. Federal Register notice of April 2, 2020 (FR Doc 2020-06354), describing the formation of CDRH's Office of Product Evaluation and Quality from offices including the Office of Compliance.
- 21 U.S.C. 321(b), definition of "interstate commerce" in the FD&C Act.