Medical device companies must maintain multiple, overlapping documentation files to comply with different regulatory requirements. FDA requires DHF (Design History File), DMR (Device Master Record), and DHR (Device History Record). ISO 13485 refers to a DDF (Design and Development File). The EU MDR 2017/745 requires Technical Documentation (TD), defined in Annexes II and III—sometimes referred to informally as a “Technical File.” Note: throughout this article, the abbreviation “MDF” is used as a shorthand for the EU MDR Technical Documentation; this is not an official EU MDR term and should be read as “Technical Documentation (TD)” in a regulatory context. Each file serves a different purpose, addresses different audiences (design engineers vs. manufacturing vs. regulators), and must be maintained for different durations. Confusion between these acronyms and files leads to incomplete documentation, gaps in regulatory submissions, and FDA warning letters. Understanding the purpose of each file and how they interconnect is essential for regulatory compliance.

Why Medical Device Documentation Is So Confusing — And Why It Matters

Regulatory requirements evolved historically and were not designed with clarity or consolidation in mind. The FDA issued 21 CFR Part 820 in 1996, establishing the DHF, DMR, and DHR framework. ISO published 13485 in 1996, which refers to a Design and Development File but aligns closely with FDA concepts. The EU MDR, enacted in 2017, introduced the MDF as a consolidated file for European regulatory submission. These standards overlap significantly but use different terminology and place emphasis on different aspects of documentation. A medical device company pursuing multiple regulatory markets must maintain documentation meeting all three frameworks.

Why does this matter? Incomplete documentation puts patients at risk. If design verification data is missing from the DHF, regulators cannot assess whether the device was adequately tested. If manufacturing procedures are inadequate in the DMR, production devices may not meet specifications verified during design. If the MDF is incomplete, the EU regulator may reject a CE marking application. The cost of reworking documentation after a regulatory submission is rejected or post-market is far higher than maintaining complete documentation during development.

The Five Core Documentation Artifacts

DHF — Design History File (FDA / 21 CFR Part 820)

The DHF is the complete technical record of the design process. It documents how the device was designed, verified, and validated. DHF contents include design input requirements, design output specifications, design review records, design verification test plans and results, design validation study protocols and results, risk management file (ISO 14971 documentation), design change records, and design transfer documentation. The DHF serves as evidence that the design process followed FDA requirements. FDA inspectors and pre-market reviewers examine the DHF to assess design rigor and completeness.

The DHF is maintained by the design/engineering team and is retained for the lifetime of the device design plus additional periods specified by regulation (typically 2 years after last distribution for some products, longer for implants). The DHF is company proprietary and is generally not provided to customers or the public. However, key summaries from the DHF (design input and output summaries, V&V summaries) are often included in regulatory submissions (510(k), PMA, CE dossier).

DMR — Device Master Record (FDA / 21 CFR Part 820)

The DMR is the permanent manufacturing specification. It documents how devices must be manufactured, tested, and inspected. DMR contents include device specification drawings, material specifications, manufacturing procedures, in-process inspection procedures, final inspection procedures, labeling specifications, packaging specifications, and storage/handling requirements. The DMR pulls directly from design outputs and ensures that manufacturing consistently produces devices meeting verified specifications.

The DMR is maintained by the manufacturing/quality team and is actively used during production. It is updated via change control whenever manufacturing procedures, specifications, or quality procedures change. The DMR must be retained for the lifetime of the device design. FDA regulations require that manufacturers maintain the ability to reconstruct manufacturing conditions for any device distributed, so the DMR and change control records are essential.

DHR — Device History Record (FDA / 21 CFR Part 820)

The DHR is the production record for a specific manufactured device or batch. It documents that a device was manufactured according to the DMR and met all specifications. DHR contents include lot/batch identification, dates of manufacture, manufacturing personnel, results of in-process inspections, final inspection results, test data, material certificates of conformance, and release/distribution records. The DHR is created during manufacturing and is retained after distribution.

The DHR serves quality assurance and post-market surveillance functions. If a device failure or adverse event occurs in the field, investigators can retrieve the DHR to determine which lot/batch was involved, what materials were used, what tests were performed, and what results were obtained. The DHR provides evidence of device traceability and quality at the point of manufacture. DHR records are typically retained for the lifetime of the device in service plus additional periods (often 5–10 years post-distribution).

DDF — Design and Development File (ISO 13485)

The DDF is the ISO 13485 equivalent to the FDA DHF. It documents design input, design output, design review, design verification, design validation, risk management, and design change. The terminology and structure differ slightly from FDA requirements (ISO prefers "design review" to FDA's separation of design review, design verification, and design validation), but the substance is similar. The DDF must be retained according to organization procedures, and this period should be specified in the quality manual.

For organizations pursuing both FDA and ISO 13485 certification, the DDF and DHF often overlap significantly. Many companies maintain a single integrated design file that satisfies both FDA and ISO requirements.

Technical Documentation (TD) — EU MDR 2017/745, Annex II & III [referred to as “MDF” in this article

The Technical Documentation (TD) is the consolidated file required for CE marking under the EU MDR. It serves a different purpose than the DHF/DMR/DHR framework. The TD is the file that the notified body reviews during product conformity assessment, and it is the file that competent authorities review during market surveillance. TD contents include device description, design file (design inputs and outputs), risk analysis and management, verification and validation (V&V), clinical evaluation, safety and clinical performance summary, and manufacturing information. The TD must be retained for the lifetime of the device plus additional periods specified by the MDR (often 15 years post-production for implantable devices; at least 10 years for other devices).

The MDF is typically more consolidated than the FDA framework. Where FDA separates design history from manufacturing and post-market records, the MDF combines design, manufacturing, clinical, and safety information into a single file. The MDF is also more accessible to regulators; notified bodies have routine access to the MDF as part of conformity assessment, whereas FDA DHF access is typically limited to pre-market submissions and official inspections.

DHF vs. DDF: Same Concept, Different Standards

The DHF (FDA) and DDF (ISO 13485) are functionally equivalent: both document the design process and serve as evidence of design rigor. The structures differ slightly. The FDA DHF emphasizes design input, design output, design review (separate event), design verification, and design validation (separate event). ISO 13485 combines design review and emphasizes design input, design output, design review with defined acceptance criteria, design verification (conformance to design output), and design validation (conformance to user needs).

In practice, a company pursuing both FDA and ISO certification typically creates a single design file that documents design input, output, review, verification, and validation in a way that satisfies both frameworks. The file is labeled DHF/DDF to indicate it meets both standards. The risk management file (ISO 14971) is usually maintained as a separate artifact but is cross-referenced in the DHF/DDF.

DMR vs. DHR: Production Instructions vs. Production Records

The DMR and DHR are complementary but distinct. The DMR is prescriptive: it documents how to manufacture, test, and inspect devices. The DHR is descriptive: it documents what was actually manufactured, tested, and inspected. Think of it this way: the DMR is the recipe, and the DHR is the record of what was actually cooked. The DMR is dynamic and changes as manufacturing evolves. The DHR is static; once created, it documents a specific batch and is never changed (though errors can be corrected with documented corrections, not deletions).

Traceability must link them. A manufacturing procedure documented in the DMR must be executed, and results must be recorded in the DHR. An inspector reviewing the DHR for a specific batch should be able to identify which DMR version was used for that batch and whether the procedures were followed correctly.

Which Documentation Do You Need? A Practical Guide by Regulatory Context

FDA 510(k) or premarket approval (PMA): Manufacturer must maintain DHF and must provide DHF summaries (design input summary, design output summary, design verification summary, design validation summary) in the submission. Manufacturer must maintain DMR and DHR to demonstrate manufacturing capability and quality. FDA may request complete DHF, DMR, or DHR records during inspections.

ISO 13485 certification: Manufacturer must maintain DDF, which should cover design input, output, review, verification, and validation. The DDF can be integrated with the DHF to meet both FDA and ISO requirements. Manufacturer must maintain manufacturing specifications (equivalent to DMR) and production records (equivalent to DHR).

EU MDR CE marking: Manufacturer must maintain MDF, which consolidates design, manufacturing, clinical, and safety information. The notified body reviews the MDF to assess conformity. Manufacturer must retain MDF for specified periods for competent authority access during surveillance.

International markets (Canada, Japan, others): Each market has its own documentation requirements. Consult regional guidance to determine what design, manufacturing, and post-market documentation is required. Many manufacturers maintain DHF/DDF plus MDF to cover multiple markets.

How the Documents Connect: A Traceability Perspective

The five documentation files are not isolated; they are interconnected through traceability. Design inputs in the DHF/DDF specify what the device must do. Design outputs in the DHF/DDF specify how those inputs will be achieved. Design verification in the DHF/DDF tests that outputs meet inputs. Design validation in the DHF/DDF tests that the device meets user needs.

The DMR translates verified design outputs into manufacturing specifications and inspection procedures. Manufacturing teams use the DMR to guide production. Each device or batch manufactured according to the DMR is documented in the DHR. The DHR shows that manufacturing followed the DMR and that the device met specifications.

For EU submissions, the MDF consolidates key elements of the DHF (design rationale, verification/validation summaries) with manufacturing information (to demonstrate manufacturing control) and clinical data (to support safety and performance claims). Traceability in the MDF shows how the design addresses user needs and how the design and manufacturing controls mitigate identified risks.

Common Mistakes When Managing Medical Device Documentation

Confusing DHF and DMR responsibilities: Design team assumes manufacturing documentation is complete, but the manufacturing/quality team is not aware documentation is their responsibility. Files are scattered, incomplete, and unavailable when needed. Solution: Clearly assign responsibility for each file. Design team owns DHF/DDF. Manufacturing team owns DMR. Quality team owns DHR. Establish a document control procedure specifying who maintains each file.

DHF/DDF created after design is complete: Documentation is treated as a compliance checkbox after the device is already designed and verified. Gaps and inconsistencies are discovered late. Solution: Create design files concurrently with design activities. Document design inputs before design begins. Create design outputs as specifications are developed. Document design reviews, V&V, and design changes in real time.

DMR not updated with design changes: A design change is made, and the DHF is updated, but the DMR is not. Manufacturing continues using outdated specifications. Solution: Change control procedures must specify that any design change triggers an assessment of DMR impact. If the DMR must be updated, change control approval must include manufacturing/quality sign-off.

DHR records incomplete: Final inspection and testing results are not fully documented. Lot traceability is incomplete. Solution: Implement a production record system (paper or electronic) that ensures all required quality data (in-process inspection, final testing, material certificates) are collected, documented, and retained for each batch.

MDF prepared only at time of regulatory submission: The MDF is hastily assembled from existing DHF and DMR files only when CE marking is imminent. Inconsistencies and gaps are discovered during notified body review, causing submission delays. Solution: Develop the MDF concurrently with design and manufacturing activities. Use the MDF as the primary regulatory strategy document, and periodically update it as design and manufacturing evolve.

💡 Matrix Req consolidates design, manufacturing, and regulatory documentation in a unified system. Design inputs, outputs, verification, and validation are documented in a file structure aligned with FDA DHF and ISO 13485 DDF requirements. Manufacturing specifications auto-populate from verified design outputs, ensuring DMR accuracy. Change control with downstream impact analysis ensures that any design change cascades to manufacturing and is reflected in affected quality procedures. Compliance reporting generates DHF summaries, DMR documentation, and MDF sections automatically. Traceability reporting demonstrates that design flows through manufacturing and post-market with complete documentation, enabling rapid regulatory submissions and confident audit preparation.