Accessories for Medical Devices
What a lot of people understand by accessories is different from the definition of the term in the German Medical Devices Act (MPG).
This article gives you an overview of the definition of the term, the regulatory requirements and typical questions.
1. Definition of the term “accessory”
a) Accessory according to the MPG and MDD
The German Medical Devices Act defines the term as follows:
“Accessories for medical devices are articles, substances and preparations made from substances which do not in themselves constitute medical devices according to number 1, but are intended by the manufacturer to be used in combination with a medical device so as to enable the latter to be used for its intended purpose as specified by the manufacturer."
b) Accessory according to MDR
The Medical Device Regulation (MDR) uses almost word-for-word the same definition for the term:
“... an article which, whilst not being itself a medical device, is intended by its manufacturer to be used together with one or several particular medical device(s) to specifically enable the medical device(s) to be used in accordance with its/their intended purpose(s) or to specifically and directly assist the medical functionality of the medical device(s) in terms of its/their intended purpose(s)”.
Examples of accessories include foot switches and remote controls for operating tables, cleaning agents, tools for installing, calibrating and maintaining medical devices, and special supports and covers.
We explain what differentiates an accessory from a spare part below.
c) “Accessory” according to the FDA
For the FDA, a medical device is
“an instrument, apparatus, implement, machine, contrivance, implant, in vitro reagent, or other similar or related article, including a component part, or accessory which is:
- […] intended for use in the diagnosis of disease or other conditions, or in the cure, mitigation, treatment, or prevention of disease, in man or other animals, or
- intended to affect the structure or any function of the body of man or other animals, and which does not achieve its primary intended purposes through chemical action within or on the body of man or other animals and which is not dependent upon being metabolized for the achievement of any of its primary intended purposes.”
This makes it clear that an accessory is also a device and that the corresponding regulations apply. The FDA also explicitly defines the term accessory:
“A finished device that is intended to support, supplement, and/or augment the performance of one or more parent devices.”
It is therefore also possible for an accessory to have to go through a Premarket Approval (PMA), Premarket Notification (PMN, 510(k))or a De Novo process.
According to the quotation above, the FDA, in principle, classifies accessories in the same class as the “parent device”, unless there are different risks for the accessory and the parent device. The accessories are then independently classified according to these risks.
If accessories are intended for use with more than one “parent device”, then that is a further reason for a different classification.
More information can be found in the FDA Guidance Document “Medical Device Accessories – Describing Accessories and Classification Pathways”.
3. Can software be an accessory for a medical device?
Question: Is (stand-alone) software for the calibration of a medical device a medical device itself? Or is it an accessory for a medical device? Or neither?
This simple sounding question is, in fact, not so easy to answer. To answer it, we have to look at the history of the definition of the term.
Unlike the current definition, the MPG defined the term as follows in its first version in 1994:
“Accessories for medical devices are articles, substances and preparations made from substances and software which do not in themselves constitute medical devices according to number 1, but are intended by the manufacturer to be used, [...]”
With the amendment of the MDD in 2007, the definition of a medical device was expanded to make it clearer that software can also be a medical device. This is detailed in the explanation for the amendment. The transposition into the MPG in 2009 meant that the wording of this definition was adopted and, in the same amendment, the definition of “accessory” was also updated, with “software” being deleted. But that does not mean that software can no longer be an accessory.
Conclusion: The problem therefore stems from the adoption of the definition of accessory in the MPG and is a misinterpretation of the 2009 amendments.
The recitals of the MDR state:
“The qualification of software, either as a device or an accessory, is independent of the software's location or the type of interconnection between the software and a device.”
Recital (19) MDR
b) USA / FDA
In the guidance document on accessories mentioned previously, the FDA explicitly emphasizes that standalone software (“software as a medical device” SaMD) can also be an accessory but does not have to be. However, if the software is to be used for medical purposes without hardware, the software itself is a medical device and not an accessory.
4. Same manufacturer for a medical device and its accessory
Question: Does the manufacturer of an accessory have to be the same as the manufacturer marketing the corresponding medical device? Another question is, should the words in brackets be added to following definition of an accessory?
“Accessories for medical devices are articles, substances and preparations made from substances which do not in themselves constitute medical devices according to number 1, but are intended by the manufacturer (of the “accessory”) to be used in combination with a medical device (the “parent device”) so as to enable the latter (the “parent device”) to be used for its intended purpose as specified by the manufacturer (of the accessory).”
Answer: No. It cannot be assumed that it is meant to be the same manufacturer. This is also reflected in the "reality" that they are often different manufacturers. For example, for dialysis machines, the market for blood tubes is a competitive one.
By the way: This is precisely why, for example, a lot of manufacturers design their devices in a way that makes life hard for manufacturers of accessories, particularly disposable accessories, for the device, to ensure that users buy “original accessories”.
5. Accessories versus spare parts
Question: What happens if you sell a peristaltic pump for a dialysis machine? Is it now an accessory or is it a spare part?
- It could indeed be an accessory, because by definition an accessory is an article intended by the manufacturer to be used with a medical device so that the medical device can be used for the intended purpose as specified by the manufacturer. And a peristaltic pump is certainly used to ensure that the dialysis machine can be used for its intended purpose.
- It could also be a spare part because a defective peristaltic pump has to be replaced.
The first answer to the question is: It doesn't have to be either-or. Products can be both spare parts and accessories. Let's take a look at this specific case:
If you do not sell the peristaltic pump independently, but only offer it as a spare part, then it is a spare part. In other words, the peristaltic pump does not have to undergo its own conformity assessment procedure. Instead, you can check the conformity of the dialysis system as a whole, including the peristaltic pump.
If, on the other hand, you market the peristaltic pump as an optional product, you need a conformity assessment. It is then an accessory. The fact that it can be used as a spare part does not change anything.
Whether a peristaltic pump is a spare part or an accessory depends on the type of communication and declaration.
6. Risk management for accessories
The risk management for an accessory cannot be done in ignorance of the medical device it is to be used with.
Risk management should also not just repeat the elements of risk management for the device, it also has to add the elements resulting from the specific use and design of the accessory. Therefore, FMEA is a useful method for the risk analysis of an analysis.