When you look at a medical device, it’s easy to take it at face value without realizing the tremendously detailed design and manufacturing processes that went into creating it. However, behind each piece of equipment, years (and occasionally decades) of effort went into every step from initial conception to the current batch, lot and unit number for that individual machine. However, despite this almost overwhelming level of detail, there’s one place you can go to find a comprehensive summary: the Device Master Record (DMR).

What is a Device Master Record?

A DMR is a record of every piece of information needed to produce a medical device, from start to finish. The format is less important than the content and could consist of a robust three-ring binder, although that is rarely the case in the era of cloud computing. Requirements for what to include aren’t ad hoc but are explicitly specified by the FDA in 21 CFR Part 820.181. Here is the relevant passage:

Each manufacturer shall maintain device master records (DMRs). Each manufacturer shall ensure that each DMR is prepared and approved in accordance with 820.40. The DMR for each type of device shall include, or refer to the location of, the following information:

(a) Device specifications including appropriate drawings, composition, formulation, component specifications, and software specifications

(b) Production process specifications including the appropriate equipment specifications, production methods, production procedures, and production environment specifications

(c) Quality assurance procedures and specifications including acceptance criteria and the quality assurance equipment to be used

(d) Packaging and labeling specifications, including methods and processes used

(e) Installation, maintenance, and servicing procedures and methods.

The DMR must also include any tangible designs, such as a plastic mold for a particular component. Although there is significant overlap between the two, it’s critical to understand that the driving reason behind a DMR is separating the design and production processes. The design process is fully recorded elsewhere.

How is the DMR Different from the DHF & DHR?

A good device record consists of three different things, one of which is the DMR. The other two are the Design History File (DHF) and the Device History Record (DHR). Think of the differences this way: the DHF is a comprehensive record of the device design, the DHR is a full record of the device’s manufacturing history, and the DMR contains an overall summary of everything you need to know to produce the device.

The DMR draws heavily from the DHF for all the specs necessary to guide the manufacturing process, but doesn’t concern itself with the ins and outs of why a component was designed a certain way or have any records about alternate constructs that were ultimately discarded. The DHF, however, will document each milestone of the design process. A good Design History File will have records starting with establishing user needs through final prototype development. Other departments or designers should be able to access the DHF anytime they want to replicate some design aspect. The DHF should have everything the designer would need to accomplish that without looking outside the record.

Once a design is complete, the DHF becomes a largely static source of documentation. It will only change if flaws are discovered and some aspect of the machine needs to be redesigned, or if a new version of the same device is required. By and large, this is not a living document.

Conversely, the Device History Record is a living record of all lot, batch and machine numbers. When customers or audits discover issues with an individual device, the DHR will facilitate the root cause analysis and allow a manufacturer to pinpoint the problem quickly. The DMR should point to the DHR and show you where to access this dynamic history but does not need to be updated with manufacturing records.

A DMR is primarily static but also contains a record of any changes. If the type of plastic a device uses for its housing changes, that will be listed in the DMR. If a primary manufacturing facility or subcontractor changes, you’ll find that record in the DMR as well. To the degree that manufacturing processes continue uninterrupted, however, the DMR will remain unchanged.

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