Complete Guide to MDR Codes: How to Use MDA, MDN, MDS, and MDT Codes for Medical Device Compliance

MDR codes are essential for any medical device manufacturer aiming for certification under European standards. Codes MDA, MDN, MDS, and MDT make up a classification system that helps to accurately describe each device, select the right Notified Body (NB), and assign qualified auditors. This guide will walk you through each code, showing how to apply them effectively to structure your technical documentation and ensure device compliance.

Why Are MDR Codes Crucial for Compliance?

MDR codes are more than just labels—they structure the certification process by guiding the evaluation of medical devices by NBs and auditors. Each code—MDA, MDN, MDS, and MDT—serves a key purpose:

1. Choosing the right NB: Whether the device is classified as MDA or MDN determines which NBs are qualified to assess it.

2. Assigning specialized auditors: Codes MDS and MDT help designate auditors with the necessary expertise for both the technical documentation review and production audits.

3. Supporting traceability and compliance: Clear classification with these codes simplifies audits, boosts transparency, and improves device tracking.

Understanding MDR Codes: MDA, MDN, MDS, and MDT

These codes are defined by Regulation (EU) 2017/2185 and outlined in MDCG guidance 2019-14. Together, they form the foundation for device classification and direct each step of the certification process.

MDA or MDN: Establishing the Primary Classification

MDA and MDN codes determine whether a device is active or non-active, which guides the choice of an appropriate Notified Body.

• MDA (Medical Device Active): This code applies to devices that require a power source to operate, such as imaging devices or heart monitors.
• Example: A heart monitor, powered to track heart rate continuously, would be classified under MDA.
• MDN (Medical Device Non-active): This code covers devices that function without an external power source, such as implants or dressings.
• Example: A hip implant surgically implanted without needing power would be given an MDN code.

⚠️ Tip: Each device should be classified as either MDA or MDN, but not both. This primary classification is essential for the rest of the compliance process.

MDS and MDT: Additional Codes for Specific Features and Technologies

MDS and MDT codes provide further detail on a device’s unique features and manufacturing technologies, guiding the selection of specialized auditors for technical documentation and production site audits.

• MDS (Specific Device Features): This code applies to characteristics such as sterility, medicinal substances, or embedded software, guiding the choice of an auditor for the technical documentation.
• Example: A sterile implant containing an antibiotic may be assigned MDS codes for sterility (MDS 1005) and medicinal substances (MDS 1001), ensuring an auditor with expertise in sterility and pharmaceuticals is involved.
• MDT (Specific Technologies): This code identifies production technologies that require particular expertise during the on-site audit.
• Example: An implant produced in a clean room might be assigned MDT 2008, ensuring that an auditor skilled in controlled production environments conducts the on-site audit.

💡 Advice: If the device has multiple features or uses different technologies, it may be assigned multiple MDS and MDT codes, ensuring a thorough evaluation.

Why Proper MDR Code Assignment Is Crucial for Medical Devices

MDCG 2019-14 highlights the importance of correct MDR code assignment to ensure rigorous compliance and reduce non-compliance risks. Here’s why these classifications are essential:

• Optimal NB selection: The primary code (MDA or MDN) helps manufacturers choose the right NB for device evaluation.
• Ensures expert technical review: MDS codes allow the designation of auditors skilled in the specific features of the device for the technical documentation review.
• Facilitates production audits: MDT codes ensure that auditors with the right expertise evaluate the manufacturing processes during on-site audits.

Steps for Assigning MDA, MDN, MDS, and MDT Codes to Your Device

These steps will help you assign the correct codes to ensure your device meets compliance standards.

Step 1: Identify Whether the Device Is Active or Non-active (MDA or MDN)

First, determine if your device is active or non-active, as this will guide the selection of the Notified Body.

Example: A knee implant, which doesn’t require power, would be classified as MDN. A diagnostic device that needs power would be classified as MDA.

Step 2: Select MDS Codes

Once the MDA or MDN code is assigned, MDS codes are added based on the device’s specific features to designate a qualified technical documentation auditor.

Example: A sterile implant that also contains a medicinal substance would be assigned MDS codes for sterility and medicinal content, allowing an auditor with the right expertise to be appointed for the documentation review.

Step 3: Select MDT Codes

MDT codes specify the production technologies used, ensuring that the right auditors are appointed for on-site audits.

Example: An implant produced in a clean room and using animal-derived materials might be assigned MDT codes for both technologies, ensuring an appropriately skilled auditor is chosen.

Step 4: Document and Justify Codes in the Technical File

Each code must be thoroughly documented and justified in the technical file. This file provides transparency, supports the evaluation process, and demonstrates that classification choices were made carefully.

MDR Codes Are the Foundation of Medical Device Compliance

MDR codes – MDA, MDN, MDS, and MDT – are more than just identifiers. They ensure a structured, complete evaluation of medical devices, supporting both safety and compliance. Following these steps and applying the codes precisely simplifies the audit process and contributes to the high standard of quality in the European medical device market.

FAQ on MDR Codes for Medical Devices

What’s the difference between MDA and MDN codes?

MDA (active) and MDN (non-active) codes establish the device type and guide NB selection.

When should I use multiple MDS or MDT codes?

If your device has multiple features or uses different technologies, assign multiple MDS and MDT codes for a complete, targeted evaluation.

How should I document MDR codes in the technical file?

Provide justifications for each code in the technical file, explaining each feature clearly to support transparency and streamline the audit process.

Also check out our article: MDR Documentation: Avoid Common Mistakes and Follow Best Practices.