Custom-Made Medical Devices Under EU MDR: Annex XIII and the FDA Exemption
A complete guide to custom-made medical devices under EU MDR Annex XIII. Learn about the manufacturer statement, MDCG 2021-3, and FDA CDE comparison.
The Evolution of Patient-Specific Device Regulation
In an era of personalized medicine, additive manufacturing (3D printing), and advanced digital imaging, the production of medical devices tailored to individual patient anatomy has scaled dramatically. From custom orthopedic implants and patient-matched surgical cutting guides to individualized dental restorations, the medical device industry has shifted from a one-size-fits-all manufacturing model to a highly customized approach.
However, from a regulatory standpoint, "customized" does not automatically mean "custom-made."
Under the European Union Medical Device Regulation (EU) 2017/745 (EU MDR), the term custom-made medical device carries a very specific, narrow legal definition. Placing a custom-made device on the EU market requires navigating a dedicated conformity-assessment derogation under Article 52(8) and compiling the specialized documentation mandated by Annex XIII.
Importantly, the European Commission’s Medical Device Coordination Group (MDCG) published MDCG 2021-3 to draw a clear line between custom-made devices, patient-matched devices, adaptable devices, and mass-produced products.
For manufacturers operating globally, understanding how the EU MDR custom-made pathway differs from the United States Food and Drug Administration (FDA) Custom Device Exemption (CDE) is essential. The FDA’s exemption, governed by Section 520(b) of the Federal Food, Drug, and Cosmetic (FD&C) Act, is significantly narrower, imposes strict numerical volume limits, and features distinct reporting rules.
This guide provides a comprehensive operational breakdown of custom-made medical devices. We dissect the MDCG 2021-3 categorization test, outline the seven mandatory elements of the Annex XIII Section 1 manufacturer statement, list the technical documentation requirements under Annex XIII Section 2, clarify the roles of Notified Bodies and the Person Responsible for Regulatory Compliance (PRRC), and conduct a detailed, head-to-head comparison with the FDA Custom Device Exemption.
Defining Custom-Made: The MDCG 2021-3 Categorization Test
To determine which regulatory pathway applies to a patient-specific device, manufacturers must apply the definitions set out in Article 2(3) of the EU MDR and clarified in MDCG 2021-3. The guidance establishes four distinct categories of devices that are tailored or adapted for individual patients:
┌────────────────────────────────────────┐
│ Is the device manufactured based on │
│ a written prescription from an │
│ authorized professional? │
└───────────────────┬────────────────────┘
│
Yes ┌────────────┴────────────┐ No
▼ ▼
┌───────────────────────────────────┐ ┌────────────────────────┐
│ Is the device mass-produced or │ │ OUT OF SCOPE OF │
│ manufactured via industrial/serial│ │ CUSTOM-MADE ROUTE │
│ production methods? │ └────────────────────────┘
└─────────────────┬─────────────────┘
│
Yes ┌────────────┴─────────────┐ No
▼ ▼
┌───────────────────────────┐ ┌──────────────────────────────────────────┐
│ PATIENT-MATCHED DEVICE │ │ CUSTOM-MADE DEVICE │
│ - Requires standard CE │ │ - Exempt from CE mark │
│ marking & declaration │ │ - Uses Annex XIII Statement │
│ - Notified Body audits │ │ - Technical Doc (Annex XIII Sec 2) │
│ - Full MDR applies │ │ - PRRC required (Article 15) │
└───────────────────────────┘ └──────────────────────────────────────────┘
Let's examine these categories in detail to understand where your product falls:
1. Custom-Made Medical Device (Article 2(3))
A custom-made device is defined as any device specifically made in accordance with a written prescription of any person authorised by national law by virtue of their professional qualifications. This prescription must give, under that person's responsibility, specific design characteristics, and the device must be intended for the sole use of a particular patient to meet their unique clinical needs.
The key element is the specific design characteristics that cannot be met by standard, off-the-shelf devices. Examples include a custom cranial reconstruction plate designed for a patient with a highly irregular skull fracture, or a custom maxillofacial implant contoured to reconstruct a jaw after tumor removal.
2. Patient-Matched Medical Device (MDCG 2021-3)
A patient-matched device is designed and manufactured to match a patient's anatomical features (typically based on CT or MRI scans), but it is produced using industrial or serial manufacturing processes.
Even if the final shape is unique to the patient, if the device is designed within a standardized "envelope" of pre-defined parameters (such as a 3D-printed orthopedic guide that is scaled using CAD templates, or custom dental aligners printed from a master digital model), it is classified as a patient-matched device, not a custom-made device.
[!IMPORTANT] Patient-matched devices are NOT exempt from CE marking. They must undergo standard MDR conformity assessment procedures, including Notified Body review (where applicable based on class) and drawing up an EU Declaration of Conformity. For more details on the quality controls required for these products, refer to our 3D-printed medical devices regulatory guide.
3. Adaptable Medical Device
An adaptable device is mass-produced and CE-marked, but is designed to be adjusted, assembled, or cut at the point of care by a healthcare professional to fit an individual patient's anatomy. Examples include plaster casts, dental filling materials, or surgical mesh that is cut to size in the operating room. These are regulated as standard mass-produced devices.
4. Mass-Produced Device
A standard, off-the-shelf device manufactured in batches. These devices are fully subject to standard conformity assessment, require CE marking, and are designed to cover standard anatomical sizes (e.g., small, medium, large).
Detailed Case Studies: Custom-Made vs. Patient-Matched
To help engineering and regulatory teams apply these distinctions, let us look at two real-world scenarios:
Case Study A: Custom Cranial Reconstruction Plate
A patient suffers a traumatic injury resulting in a highly irregular, asymmetric skull defect. The neurosurgeon takes a high-resolution CT scan of the patient's skull, determines that none of the standard pre-shaped mesh products are clinically suitable, and writes a detailed prescription. The prescription specifies the exact thickness, material (Grade 5 titanium), suture hole placement, and contouring parameters unique to the patient's cranial bone margins. The manufacturer uses this prescription to design and print a single, one-off implant.
- Classification: Custom-made medical device. The device is created based on a specific prescription with unique design characteristics for a single patient, outside of any serial production line.
Case Study B: 3D-Printed Titanium Hip Stem
An orthopedic company offers a range of 3D-printed titanium hip stems. Instead of choosing from 10 fixed sizes, the surgeon uploads the patient's CT scan to the manufacturer's online portal. The manufacturer's CAD software automatically generates a custom stem shape that fits the patient’s femoral canal. The implant is printed using the same laser powder bed fusion (L-PBF) parameters, post-processing heat treatment, and quality inspection protocols as the company’s standard implants. The company prints 500 of these individualized implants per month for different clinics.
- Classification: Patient-matched medical device. Although the shape of each stem is customized to the patient, the device is manufactured using an industrial, serial process within a pre-validated design envelope. This product requires full MDR conformity assessment and CE marking.
Transitioning from Custom-Made to Patient-Matched: The Scalability Dilemma
Many startups in the personalized orthopedics, dental, or maxillo-facial fields begin by manufacturing custom-made devices. This is an attractive entry point: it avoids the high cost and long timelines of Notified Body clinical evaluations and standard CE marking (for lower-risk classes). However, as these companies grow, they face a severe scalability dilemma.
┌─────────────────────────────────────────────────────────────┐
│ STARTING PHASE: CUSTOM-MADE │
│ - One-off prescriptions, manual design for each patient. │
│ - Exempt from CE mark; lower pre-market barriers. │
│ - Bottleneck: High labor costs, slow turnaround times. │
└──────────────────────────────┬──────────────────────────────┘
│ Volume grows, company wants
│ to scale via automated CAD/CAM
▼
┌─────────────────────────────────────────────────────────────┐
│ TRANSITION PHASE: THE COMPLIANCE SHIFT │
│ - Software must be validated under MDR (SaMD/design tool). │
│ - Quality System (QMS) must incorporate serial printing rules.│
│ - Notified Body must audit and issue a CE Certificate. │
└──────────────────────────────┬──────────────────────────────┘
│ Transition complete
▼
┌─────────────────────────────────────────────────────────────┐
│ MATURE PHASE: PATIENT-MATCHED │
│ - Fully CE-marked device line. │
│ - Industrial, automated manufacturing of customized parts. │
│ - Market reach expands; compliance costs are amortized. │
└─────────────────────────────────────────────────────────────┘
The Transition Requirements
When transitioning from custom-made to patient-matched production, a manufacturer must execute three major regulatory shifts:
- Design Software Validation: The CAD software used to scale or shape the device to patient scans is no longer just a drawing tool. If the software automatically generates the implant design based on anatomical algorithms, the software itself may be classified as a Software as a Medical Device (SaMD) under MDR Annex VIII Rule 11, requiring its own CE mark.
- Manufacturing Process Validation: Under standard CE marking, the manufacturing process (including 3D printing parameters, cleaning, and sterilization) must be fully validated. You must demonstrate that the process consistently produces devices meeting specifications across the entire customizable range.
- Clinical Evaluation Update: A comprehensive Clinical Evaluation Report (CER) must be generated in accordance with MDCG 2020-13, proving the safety and performance of the customizable design envelope using clinical data, rather than relying on the clinician's individual prescription to justify safety.
The Annex XIII Section 1 Manufacturer Statement
Because custom-made devices do not carry a CE mark, they cannot be accompanied by a standard EU Declaration of Conformity (DoC). Instead, the manufacturer must draw up and sign a specialized document known as the Annex XIII Section 1 Statement.
This statement must accompany the custom-made device to the end-user (the prescribing clinician and the patient).
The Seven Mandatory Elements of the Annex XIII Statement
The manufacturer statement must contain the following seven explicit pieces of information:
- Device Identification Data: Specific data allowing the identification of the device (such as a description, serial number, batch number, or unique code).
- Manufacturer Identification: The name and address of the manufacturer, and the addresses of all manufacturing sites where the device was fabricated.
- Exclusive Patient Statement: An explicit, unambiguous statement declaring that the device is intended for the exclusive use of a particular patient or user, identified by name or a unique patient code.
- Prescriber and Health Institution Data: The name of the medical practitioner, dental practitioner, or other authorized person who wrote the prescription and, where applicable, the name of the health institution.
- Specific Characteristics: The specific characteristics of the product as indicated by the prescription (e.g., precise anatomical dimensions, material specifications, or design parameters).
- GSPR Conformity Declaration: A statement declaring that the device conforms to the General Safety and Performance Requirements (GSPRs) set out in Annex I of the MDR. Crucially, the statement must list which GSPRs have not been fully met, accompanied by a detailed clinical and regulatory justification.
- Biological or Medicinal Substances: Details of whether the device incorporates, as an integral part, a medicinal substance (including human blood or plasma derivatives), or tissues or cells of human or animal origin.
To ensure your documentation is aligned with standard formats, compare this statement structure with our guide on the standard EU MDR declaration of conformity.
Technical Documentation Requirements Under Annex XIII Section 2
Just because a custom-made device is exempt from standard CE marking does not mean the manufacturer is exempt from documentation requirements. Under Annex XIII Section 2, the manufacturer must compile and maintain a robust technical file.
This documentation must be kept available for the competent authorities for a period of at least 10 years after the device has been placed on the market. For implantable custom-made devices, this record-keeping period is extended to at least 15 years.
Required Elements of the Technical File
The technical file for a custom-made device must include:
- Manufacturing and Process Data: Documentation detailing the manufacturing process, the raw materials used, the validation of manufacturing equipment (especially critical for 3D printers or CNC machines), and the quality control tests performed.
- Design Specifications: Drawings, circuit diagrams, design calculations, software code validation, and a detailed description of the design characteristics specified in the prescription.
- Risk Management File: A complete risk-management file demonstrating that hazards have been identified, risks have been reduced to acceptable levels, and the benefit-risk ratio is favorable.
- Clinical Evaluation Report (CER): A CER must be compiled showing that the clinical performance and safety of the device are supported by scientific literature, clinical experience, or specific clinical studies.
- Post-Market Surveillance (PMS) Plan: A PMS plan detailing how the manufacturer will actively monitor the device's performance in the market, collect feedback from the prescribing clinician, and compile Periodic Safety Update Reports (PSURs) where applicable.
Specific Testing and Standards Expectations
Notified Bodies and competent authorities expect technical files to reference harmonized standards where relevant:
- Mechanical Integrity: If you manufacture custom-made dental implants or orthopedic joints, you must maintain data supporting the mechanical limits of your designs, referencing standards such as ISO 14801 (for dental implant fatigue testing) or ISO 7206 (for hip joint implants), even if you cannot run a fatigue test on every single custom unit.
- Biocompatibility: The materials used must be fully qualified under the ISO 10993 series. You must maintain raw material certificates and validation files proving that the specific manufacturing process (e.g., printing and post-cure washing) does not introduce toxic residues.
- Sterilization Validation: If the device is supplied non-sterile for sterilization at the hospital, your technical documentation must contain validated sterilization instructions in accordance with ISO 17665-1 (moist heat sterilization), detailing the exact parameters the hospital must use.
CE Mark, Notified Body, and PRRC Requirements
The regulatory pathway for custom-made devices features unique exemptions and obligations regarding oversight and personnel.
1. CE Marking Exemption
Custom-made devices must NOT carry a CE mark.
Because they are not subject to standard conformity assessment, placing a CE mark on a custom-made device is a regulatory violation. The only mark of compliance is the signed Annex XIII Statement.
2. Notified Body Involvement: The Class III Implantable Exception
Historically, under the MDD, Notified Bodies had zero involvement in custom-made devices. The EU MDR changed this, introducing a critical oversight gate for high-risk products.
[!WARNING] Under Article 52(8) of the MDR, if you manufacture a Class III implantable custom-made medical device (such as a custom-made joint replacement or a custom cranial implant), Notified Body involvement is mandatory.
The Notified Body does not issue a CE certificate for the device itself. Instead, they must perform an assessment of the manufacturer's Quality Management System (QMS) and the technical documentation for the custom-made product line. The manufacturer must obtain a QMS certificate from a Notified Body before placing Class III implantable custom-made devices on the market.
3. Person Responsible for Regulatory Compliance (PRRC)
Even though custom-made manufacturers do not undergo standard product certification, they must still appoint a Person Responsible for Regulatory Compliance (PRRC) under Article 15.
The PRRC is responsible for ensuring that:
- The conformity of the devices is properly checked in accordance with the quality system before a device is released.
- The Annex XIII Statement is drawn up and signed.
- The technical documentation (Annex XIII Section 2) is compiled and maintained.
- The post-market surveillance obligations are met.
For a complete breakdown of the qualifications, liability, and duties of this role, refer to our guide on the PRRC person responsible for regulatory compliance and ensure your QMS references the EU MDR GSPR Annex I essential requirements.
Direct Comparison: EU MDR Custom-Made vs. FDA Custom Device Exemption
Manufacturers exporting patient-specific devices to both the European Union and the United States must understand that the EU and US regulatory definitions and requirements do not align. The US FDA Custom Device Exemption (CDE) is far more restrictive than the EU MDR custom-made pathway.
The FDA Exemption Framework
The FDA CDE is established under Section 520(b) of the FD&C Act. The custom device definition is codified at 21 CFR 812.3(b), the exemption from 510(k) premarket notification is at 21 CFR 807.85(a), and the exemption from PMA and performance-standard requirements flows from section 520(b) itself. The FDA clarifies its operational expectations in its guidance Custom Device Exemption.
To qualify for the FDA Custom Device Exemption, a product must meet five strict statutory tests:
- It is created for a particular patient named in the order.
- It is designed to treat a condition that no other domestic device is available to treat.
- It is not generally available to, or used by, other physicians.
- It is not commercially distributed in finished form.
- It is manufactured to meet the special needs of a physician in the course of their professional practice.
The Strictest Boundary: The 5-Unit Volume Limit
The most significant operational difference is that the FDA imposes a strict aggregate numerical limit on custom device production.
Under the CDE, a manufacturer is limited to no more than 5 units per year of a particular device type. The FDA interprets this as five new custom device "allotments" per calendar year — that is, five new patients for a patient-focused custom device, or five new physicians for a physician-focused custom device — and the cap includes all devices of that type the manufacturer provides to ordering physicians and/or patients across all facilities. The limit is therefore manufacturer-wide for a given device type, not a per-facility allowance. If a manufacturer exceeds five units of a device type in a calendar year, the product loses its custom exemption and must obtain a standard 510(k) clearance or PMA approval.
The EU MDR has no specific numerical limit on the number of custom-made devices a manufacturer can produce, provided each unit is genuinely custom-made (prescribed with unique design characteristics) and is not serial-produced.
Oversight and Reporting Comparison
The table below provides a side-by-side, head-to-head comparison of the EU and US pathways:
| Regulatory Parameter | EU MDR Custom-Made Pathway | US FDA Custom Device Exemption (CDE) |
|---|---|---|
| Legal Basis | Article 52(8) and Annex XIII | FD&C Act Section 520(b); 21 CFR 812.3(b) & 807.85(a) |
| CE Mark / Clearance | Exempt from CE marking. | Exempt from 510(k) and PMA. |
| Oversight Gate | Notified Body QMS certification required for Class III implantable custom-made devices. | No pre-market review, but subject to annual reporting to the FDA of all custom devices distributed. |
| Volume Cap | No numerical cap, but must not be serial-produced (MDCG 2021-3). | Aggregate cap of no more than 5 units per year of a particular device type (5 new patients or 5 new physicians). |
| Prescription Source | Written prescription from any person authorized by national law. | Written order from a licensed physician or dentist. |
| Patient Statement | Annex XIII Section 1 Statement must accompany every device. | No specific patient-facing statement, but clinical records must support the unique need. |
| Record-Keeping | 10 years (15 years for implantable devices). | Per 21 CFR 820.180 (now aligned with ISO 13485 via the QMSR), records retained for the effective life of the device (minimum 2 years from commercial release). |
Sponsors seeking to navigate standard FDA pathways for patient-matched products that fail the CDE test should review our guide on FDA de novo classification to determine alternative market-access strategies.
Action Checklist for Patient-Specific Device Manufacturers
If your facility designs or fabricates devices tailored to individual patients, follow this checklist to ensure compliance:
- Run the MDCG 2021-3 Test: Audit your design and production files to verify if your device is legally custom-made, patient-matched, or adaptable.
- Check Notified Body Scope: If you manufacture Class III implantable custom-made devices, contact your Notified Body to schedule a QMS and technical documentation audit under Annex XIII Section 2.
- Draft the Annex XIII Statement Template: Create a standardized Annex XIII Section 1 statement template containing all seven mandatory elements.
- Establish a Custom File Folder: For every custom-made device, compile a folder containing the clinical prescription, specific design drawings, manufacturing logs, and risk assessments.
- Review US Volume Logs: If exporting to the US under the CDE, implement automated software logs to track and alert your sales team if any facility approaches the 5-unit annual limit.
Frequently Asked Questions
Can a 3D-printed patient-specific implant be classified as custom-made under MDR?
Only if it is manufactured outside serial or industrial processes. Under MDCG 2021-3, if a 3D-printed implant is designed within a standardized template or "envelope" of digital parameters and printed using a serial manufacturing process, it is classified as a patient-matched device. Patient-matched devices require standard CE marking and cannot use the custom-made derogation.
Does a custom-made device need Notified Body involvement?
Generally, no. However, under Article 52(8) of the EU MDR, manufacturers of Class III implantable custom-made medical devices must obtain Notified Body certification for their Quality Management System (QMS) and have their custom-made technical documentation audited before placing the devices on the market.
What is the difference between custom-made and patient-matched devices under MDCG 2021-3?
A custom-made device is designed and manufactured based on a unique prescription with specific design characteristics for a single patient, outside serial production. A patient-matched device is designed and manufactured to match a patient's anatomy, but is produced using industrial, serial, or template-based manufacturing methods. Patient-matched devices must carry a CE mark.
Does a custom-made device manufacturer need to appoint a PRRC?
Yes. Under Article 15 of the MDR, all medical device manufacturers — including those who only manufacture custom-made devices — must designate at least one Person Responsible for Regulatory Compliance (PRRC) who meets the legal qualifications.
What happens if I exceed the 5-unit limit for an FDA custom device?
If you distribute more than 5 units of a particular device type in a calendar year (counted across all physicians and facilities combined), the device loses its custom device exempt status. The FDA will consider any further distribution of the device to be commercial distribution of an unapproved device, which is a violation of the FD&C Act. You must obtain standard 510(k) clearance or PMA approval to continue distribution.
How do clinical evaluation requirements differ for custom-made devices compared to standard CE-marked devices?
While standard devices require a comprehensive Clinical Evaluation Report (CER) showing statistical safety across clinical trials, custom-made devices utilize a modified clinical evaluation under Annex XIII Section 2. The CER must still prove clinical safety and performance using available literature, historical pre-clinical testing, and clinical follow-up records. However, because each device is unique, the evaluation focuses on the safety of the design process and materials rather than statistical trial data of the final custom geometry.
Can a hospital or clinician be considered the manufacturer of a custom-made device if they print it in-house?
Yes. If a hospital or clinic fabricates a custom-made device using in-house 3D printers, they assume the legal responsibilities of the manufacturer. However, under MDR Article 5(5), health institutions are granted certain exemptions (the "in-house exemption") for devices manufactured and used exclusively within the same institution, provided they meet specific QMS requirements, draw up a declaration, and justify that the target patient group's needs cannot be met by an equivalent CE-marked device on the market.
References
- Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices (EU MDR). EUR-Lex.
- Medical Device Coordination Group (MDCG). MDCG 2021-3 - Questions and Answers on Custom-Made Devices. published March 2021. EC Public Health.
- U.S. Food and Drug Administration (FDA). Custom Device Exemption - Guidance for Industry and Food and Drug Administration Staff. FDA Guidance.
- TUV SUD. Annex XIII - Procedure for custom-made devices under EU MDR. TUV SUD Info.
- Norwegian Medical Products Agency (DMP). Custom-made devices guidance and manufacturer registration. DMP Portal.