Small codes, big impact: How to get your MDR codes right

Incorrect or incomplete MDR codes can delay time to market. Here’s how they work and how to choose them.

When you apply to a Notified Body for certification under EU MDR, you’re asked to enter codes – known as MDR codes – that describe your device, its specific characteristics, and how it’s made.

It would be easy to hurry through this task, but MDR codes shape the whole certification process – from which specialists examine your device to how long your assessment takes.

Getting it right can avoid back-and-forth with your Notified Body, a mismatch in the experts assigned to your device, and ultimately a delay in your device's launch.

What are MDR codes?

MDR codes were created under the EU MDR to describe medical devices and to establish whether a given Notified Body is authorised to certify your type of device. When you enter an MDR code on an application to a Notified Body, that Body will check the code against its own approved scope and use it to assign specialists to your application.

Each device will have one main code to describe what it is and what it does, plus ‘horizontal’ codes to describe the device’s specific characteristics and manufacturing methods. 

The main code: MDA or MDN

There are two categories of main code: 

1. MDA codes apply to ‘active’ devices that use external energy, such as heart monitors, X-ray machines and software. There are 26 options.

2. MDN codes apply to ‘non-active’ devices that do not rely on energy to function, such as hip implants, syringes, and IV bags. There are 18 options. 

Horizontal codes: MDS and MDT

Beyond the main code, there are two types of horizontal codes, which cover any specific characteristics and how the device was made: 

1. MDS codes indicate specific characteristics, such as being sterile, containing a medicine, or measuring something. There are 14 options. Not every device will need these codes, but if yours does, completing them correctly will help get the right experts assigned to your device. 

2. MDT codes identify the main methods and processes used to build the device, such as manufacturing using clean rooms, biotechnology or chemical processing. There are 13 options, and every device has at least one. 

The full lists appear in Implementing Regulation 2017/2185, with accompanying guidance in MDCG 2019-14.

A quick guide to MDR codes

Choosing your main code

The first step is to decide on your main MDA/MDN code. This is often straightforward, but there may be cases where a device fits more than one. In that instance, MDCG 2019-14 says to choose the applicable code that appears highest on the list in Implementing Regulation 2017/2185. 

Why? The list is ordered so that the codes requiring the most specialised technical knowledge come first. Picking the highest applicable code means your device is matched with reviewers who have that expertise.

Take the example of a laser for eye surgery. It plausibly fits three codes:

• MDA 0302: active non-implantable devices utilising non-ionising radiation 

• MDA 0309: active non-implantable ophthalmologic devices

• MDA 0312: other active non-implantable surgical devices

The rule says to take the code highest in the list, so it’s MDA 0302. This makes sense, because working with non-ionising radiation calls for the most specialised expertise of the three.

When deciding on your main code, it's important to consider every code that might fit, rather than stopping at the first plausible match.

A method for assigning your codes

Your Notified Body has the final word on which codes apply to a device, but the manufacturer’s proposal sets the starting point. The following is a potential internal method for organising your code selection, not a required process. Start with a working outline that includes your device’s intended purpose, specific characteristics and manufacturing processes, then use it to check that your chosen codes are relevant and complete.

A suggested approach to code selection

Consider the following steps to determine your MDR codes:

1. Create a working outline of your device. Use your existing intended purpose statement as the starting point, then list the device’s specific characteristics and the main processes used to manufacture it. This outline is simply an internal working aid, not a required document or template. Break this information into individual points, then compare them with the code descriptions to help identify which codes apply.

2. Fix the main code before anything else. Decide whether the device is active (MDA) or non-active (MDN) and find the single code that best captures its design and intended purpose. Where more than one could fit, take the one earliest in the list. (See the section above, ‘Choosing your main code’, for a full explanation.)

3. Add the horizontal codes. Use your device’s characteristics to choose your MDS codes and your manufacturing methods to choose your MDT codes. Only add a code where the device genuinely has that characteristic.

4. Check each code against your working outline. This check can help catch issues in both your outline and your code list. A code with no corresponding characteristic or process in your outline may not be relevant to your application. Conversely, a characteristic or process listed in your outline with no matching code may indicate that a code was missed. The clean map from outline to codes can also form the rationale you submit to your Notified Body.

Put the work in early

Choosing your MDR codes carefully gives your Notified Body a clear, defensible account of your device and the expertise needed to assess it. Putting in the work up front makes the process faster and more accurate. For manufacturers, that’s something worth spending a bit of time on.