Predicate Device

A Predicate Device is a legally marketed medical device to which a new device is compared to demonstrate substantial equivalence in a 510(k) premarket notification submission. The predicate serves as the benchmark for establishing that the new device is as safe and effective as a device already on the U.S. market.

Legal basis and requirements:
Under Section 510(k) of the Federal Food, Drug, and Cosmetic Act, a device is substantially equivalent if it:
- Has the same intended use as the predicate device
- Has the same technological characteristics, OR
- Has different technological characteristics but does not raise new questions of safety and effectiveness AND demonstrates equivalence through performance data

Characteristics of a valid predicate:
A predicate device must be:
- Legally marketed - Currently or previously legally marketed in the U.S. (not banned, declared adulterated, or subject to certain FDA orders)
- Pre-amendment device - Marketed before May 28, 1976, OR
- 510(k)-cleared device - Cleared through the 510(k) process, OR
- PMA-approved device - Approved through the PMA process, OR
- De Novo granted device - Granted marketing authorization through the De Novo pathway
- Not Class III - Generally, Class III devices requiring PMA cannot serve as predicates (with limited exceptions)

Intended use comparison:
The subject device and predicate must have the same intended use, which includes:
- Same general purpose and function
- Same conditions of use (patient population, clinical indications)
- Same anatomical site or body system
- Similar claims and labeling
- Note: Devices can have the same intended use even if minor differences exist in specific claims

Technological characteristics comparison:
When comparing technological characteristics, manufacturers evaluate:
- Materials - Composition of device materials (metals, polymers, biologics)
- Design - Physical configuration, dimensions, components
- Energy source - Electrical, mechanical, thermal, acoustic, optical
- Operating principle - Mechanism of action and function
- Software algorithms - For devices with software functionality
- Sterility - Sterile vs. non-sterile configurations

Multiple predicates:
FDA allows use of multiple predicate devices when:
- Different aspects of the subject device are compared to different predicates
- Each predicate comparison addresses specific technological characteristics
- The combination of predicates comprehensively establishes substantial equivalence
- All predicates are legally marketed and appropriate references

Split predicates:
A "split predicate" strategy compares:
- Intended use to one predicate device
- Technological characteristics to a different predicate device
- This approach is acceptable if both predicates are valid and the comparison is scientifically sound
- FDA scrutinizes split predicate submissions more closely

Pre-amendment devices:
Devices marketed before the 1976 Medical Device Amendments can serve as predicates even without a 510(k):
- These "grandfather" devices were on the market before FDA regulation
- Must not have been significantly changed since 1976
- Often documented in FDA's product classification database
- Use requires careful documentation of predicate's pre-amendment status

Predicate selection strategy:
Manufacturers should consider:
1. Closest technological match - Minimize differences requiring justification
2. Recent clearances - More current predicates reflect current FDA thinking
3. Same manufacturer - Your own cleared devices simplify comparison and data access
4. Multiple options - Identify backup predicates in case primary choice is challenged
5. Publicly available information - Sufficient predicate data available through 510(k) summaries
6. Avoid problematic predicates - Devices subject to recalls, warning letters, or safety concerns

Predicate documentation requirements:
510(k) submissions must include:
- Predicate device identification (510(k) number, trade name, manufacturer)
- Intended use comparison demonstrating equivalence
- Side-by-side technological characteristics comparison
- Discussion of similarities and differences
- Performance data if technological differences exist
- Rationale for predicate selection
- Copy of predicate's 510(k) summary or statement

When predicates cannot be used:
Some situations preclude using a predicate:
- No legally marketed device with same intended use exists (De Novo pathway required)
- Subject device is Class III requiring PMA
- Subject device represents a new intended use for device type
- Predicate has been reclassified or subject to FDA restrictions
- Technological differences are too substantial

FDA challenges to predicates:
FDA may question predicate choice if:
- Intended use is not truly equivalent
- Predicate's legal marketing status is unclear
- Predicate is subject to ongoing safety review
- Predicate was cleared based on outdated standards
- Comparison does not adequately address differences

510(k) database for predicate research:
Manufacturers can research potential predicates using:
- FDA 510(k) Premarket Notification Database (searchable by product code, device name, applicant)
- Device classification database (identifies product codes and predicate examples)
- FDA guidance documents (may suggest appropriate predicates for device types)
- Professional regulatory consultants with device-specific expertise

Recent guidance considerations:
FDA's "The 510(k) Program: Evaluating Substantial Equivalence in Premarket Notifications [510(k)]" guidance (2014) emphasizes:
- Use of most recent, appropriate predicates when possible
- Thorough comparison of intended use and technological characteristics
- Adequate performance testing to support equivalence claims
- Clear rationale for predicate selection

The predicate device is the foundation of the 510(k) substantial equivalence determination. Selecting an appropriate predicate and thoroughly documenting the comparison is critical to 510(k) submission success.