GMDN to EMDN Mapping

Two Different Systems

GMDN and EMDN describe medical devices using the same general approach (a structured hierarchy of terms), but they were built at different times, by different organizations, for different purposes. Understanding why they diverge is necessary before attempting any mapping exercise.

GMDN

The Global Medical Device Nomenclature (GMDN) is maintained by the GMDN Agency, an international nonprofit established in 2003. It is based on ISO 15225 and is designed for global interoperability across national registration systems. GMDN terms are assigned as five-digit numeric codes and are used in device registrations by national authorities in over 90 countries. Access to the full GMDN term database requires a paid subscription to the GMDN Agency portal.

EMDN

The European Medical Device Nomenclature (EMDN) is maintained by the European Commission and is required under MDR Article 26 and IVDR Article 23for EUDAMED registration. It was built from Italy's CND system, which had been in national regulatory use since 2007, predating the GMDN Agency's international expansion. EMDN uses alphanumeric codes structured in a seven-level hierarchy. Access is free.

The two systems were designed for overlapping but distinct purposes. GMDN prioritizes international harmonization. EMDN prioritizes granular regulatory utility within the EU regulatory framework, particularly for post-market surveillance queries by competent authorities.

Why No Official Crosswalk Exists

The absence of an official mapping is not an oversight. It reflects structural differences between the two nomenclatures that make a reliable one-to-one crosswalk technically impractical.

Different granularity at terminal level

EMDN terminal codes are often more specific than GMDN terms. A single GMDN term may cover a device type that EMDN splits into three or four distinct terminal codes depending on configuration, material, or use setting. Conversely, some GMDN terms cover very narrow device variants that EMDN groups under a broader terminal code.

Different classification axes

GMDN organizes primarily by clinical application and physical form. EMDN organizes primarily by clinical function and anatomical domain. A device that is clearly named in GMDN under physical form may appear in EMDN under a different organizational axis entirely, making pattern-matching across the two systems unreliable.

Independent update cycles

The GMDN Agency and the European Commission update their respective systems on independent schedules. New GMDN terms do not automatically prompt new EMDN codes, and EMDN version releases do not update GMDN. The two systems drift further out of alignment with each release cycle.

What the Data Shows

In 2023, the GMDN Agency published analysis of the overlap between their term set and the then-current EMDN release. The study found that approximately 26% of GMDN terms had a directly corresponding named terminal code in EMDN, meaning a code that described the same device type by the same or equivalent clinical name.

The remaining 74% required either judgment-based mapping to a broader EMDN category, splitting across multiple EMDN codes, or accepting that the EMDN system describes the device at a different level of specificity than the GMDN term.

This means that if your organization has been using GMDN terms as a proxy for EMDN codes, approximately three-quarters of those mappings need manual review before use in a EUDAMED submission.

Practical Mapping Workflow

The most reliable approach to GMDN-to-EMDN mapping does not attempt to translate one code into another. It returns to the source: the device's clinical function as described in its Instructions for Use and intended-use documentation.

Step 1: Extract the intended use statement

Pull the intended use statement from the device's Instructions for Use or the Declaration of Conformity. This is the authoritative description of what the device does. GMDN terms and EMDN codes are both attempts to standardize this description. Starting from the source avoids carrying classification errors from one system into the other.

Step 2: Identify the clinical function

From the intended use statement, extract the primary clinical action: what does the device do to or for a patient? This is the axis EMDN uses. Examples: measures, delivers, supports, implants, monitors, collects, ablates. Clinical function determines the EMDN category before you open the browser.

Step 3: Select the EMDN top-level category

Map the clinical function to the appropriate EMDN top-level category. When more than one category seems applicable, choose the category that reflects the primary intended use, not a secondary function. A device that both measures blood pressure and delivers a drug is classified by whichever function is primary per its Instructions for Use.

Step 4: Navigate to the terminal code

Use the EMDN browser to drill down from the selected category to the terminal code. At each level, verify that the scope note matches the device's actual configuration and intended use. Stop at the first terminal code (a code with no children in the browser) that matches.

Step 5: Cross-check against the GMDN term definition

Once you have an EMDN terminal code, read the code's scope note alongside the definition of your GMDN term. They should describe the same device type, even if the language differs. If the scope notes describe materially different device types, the mapping is wrong. Return to step 3 and try a different branch.

Hard Cases

Some device types are genuinely difficult to map, not because of documentation gaps, but because the two systems categorize them under fundamentally different principles.

Combination products

Devices that combine medical device and drug or biological components are categorized in EMDN by the device component's primary function. GMDN may carry a combined-product specific term. Identify which component determines the regulatory pathway and use that component's clinical function to select the EMDN code.

Software as a Medical Device

GMDN historically categorized SaMD by its clinical application domain (e.g., cardiology software, radiology AI). EMDN Category Z organizes SaMD by the type of clinical decision or action the software supports. The mapping from GMDN to EMDN Z-codes requires evaluating the software's regulatory function rather than its clinical specialty.

Accessories to medical devices

Accessories are classified under MDR Article 2(2) as medical devices in their own right. In EMDN, accessories often appear as terminal codes within the same category as the parent device, but sometimes in a separate accessories subcategory. Check both locations before concluding that no matching code exists.

Custom-configured systems and kits

System kits that combine multiple device types under a single product listing require the primary device component to determine the EMDN code. If the kit is registered as a system or procedure pack in EUDAMED, the components each carry their own EMDN codes at the component record level.

Resources

The mapping problem is genuinely time-consuming, not technically complicated. The right approach is to treat each device independently, return to its intended use documentation, and navigate EMDN from scratch for each entry rather than translating from an existing GMDN code. That method takes longer per device, but it produces results that hold up through NB review.