The Food and Drug Administration (FDA or the Agency), the US regulating authority in the sphere of medical devices, has published a guidance document detailing how medical device accessories should be described in submissions. The document also provides additional clarification regarding classification pathways to be applied with regard to such devices. 

The latest version of the document was issued in December 2017. It is important to note that due to its legal nature, the FDA guidance does not introduce the rules the parties involved should follow but instead provides additional recommendations to be considered in order to ensure compliance with the applicable regulatory requirements. 

The Agency also states that an alternative approach could be applied, providing that such an approach is in line with the provisions of current legislation and has been approved by the regulating authority in advance. According to the general rule, interested parties are also allowed to submit their comments and suggestions with regard to the aspects addressed in the present FDA guidance. 

Regulatory Background 

The present document is intended to provide medical device manufacturers and other parties involved with additional clarification on regulatory requirements regarding accessories to medical devices intended to be marketed and used in the US. The FDA staff should also rely on the provisions of the present guidance when dealing with applications related to accessories to medical devices. 

For this purpose, the document describes in detail the definition of an accessory to a medical device and all the regulatory procedures related thereto in accordance with the current legislation – Section 513(f)(6) of the Federal Food, Drug, and Cosmetic (FD&C) Act. The approaches to the classification of accessories to medical devices described in the present guidelines are based on the risks associated thereto and also the applicable regulatory controls. 

First, the Agency states that accessories to medical devices also fall within the scope of products subject to regulation by the FDA since the definition of a medical device already includes an accessory as one of the products. Thus, the scope of the present guidance covers all products falling within the scope of the aforementioned definition. 

As it is stated in the present FDA guidance, there are two main approaches to the classification of accessories to medical devices, namely:

1. Applying the same classification as for the parent medical device by virtue of 510(k) Premarket Notification clearance, Premarket Application (PMA) approval, or express inclusion in the classification regulation or reclassification order for the parent device.

2. Issuing a unique, separate classification regulation for the accessory to a medical device.  

With regard to the second option, according to the document, the Agency may determine that a classification regulation for an accessory should be separate from that of the corresponding parent device. Such an approach usually applies to accessories intended to be used with different medical devices or ones which have unique stand-alone functions. Hence, the Agency may determine as appropriate the issuance of a separate classification regulation addressing device-specific regulatory needs. In such a case, the class under the risk-based classification an accessory would be assigned to would differ from the one applied to a parent device. The FDA applies this approach if the risk profile of an accessory differs from the risk profile of a parent device and, consequently, requires a different level of regulatory controls to provide reasonable assurance of safety and effectiveness of the accessories

Classification Principles in Detail


Additional changes to applicable regulations were introduced by the FDA Reauthorization Act 2017, which amended the appropriate provision of the FD&C Act in the following way: 

The Secretary shall … classify an accessory under [section 513] based on the risks of the accessory when used as intended and the level of regulatory controls necessary to provide a reasonable assurance of safety and effectiveness of the accessory, notwithstanding the classification of any other device with which such an accessory is intended to be used. 

Thus, according to the applicable legislation, the classification of an accessory to a medical device should be based on the risks associated thereto, as well as the controls to be imposed in order to ensure the safety and effectiveness of an accessory in question when used for the intended purpose initially indicated by its manufacturer. The Agency provides an example of when an accessory to a class III parent device may pose lower risk that could be mitigated through general controls or general and special controls and thus could be regulated as class I or class II. 

As mentioned before, the scope of the present FDA guidance covers all products falling within the scope of the definition of a medical device. In terms of accessories to medical devices, this includes:

–   an accessory that is included in an application for premarket approval … under section 515 or a report under section 510(k) for clearance of such device [intended to be used with the accessory] and the Secretary has not classified such accessory distinctly from another device”, and

–   An accessory that has been granted marketing authorization as part of a submission for another device with which the accessory involved is intended to be used, through an application for such other device under section 515(c), a report under section 510(k), or a request for classification… 

Additional Classification Rules

The Agency also states that the approach described herein should also be applied in the case of software products, including ones subject to regulations as Software as a Medical Device (SaMD). For this purpose, the FDA utilizes the SaMD definition initially developed by the International Medical Device Regulators Forum (IMDRF), a voluntary association of national regulating authorities focused on the improvement of the regulatory framework for medical devices. In this regard, the Agency also states that not all SaMD products connected with medical devices should be treated as accessories thereto. In particular, if the SaMD product in question has its own stand-alone functions, it should be subject to regulation as a separate medical device with its own intended purpose but not as an accessory to a medical device. 

The FDA mentions that in certain cases, a SaMD could be used together with another medical device as one of its modules. Consequently, such a SaMD would be considered as an accessory to that medical device if it is intended to support the operations thereof. 

However, irrespectively of the way the software operates, the regulating authority intends to apply the same approach based on the associated risks and regulatory controls. 

In summary, the present FDA guidance describes the approach the authority applies when determining the classification of accessories to medical devices. In particular, the document outlines the scope of products that meet the appropriate definition and also highlights the most important aspects to be considered when making such a determination. 

How Can RegDesk Help?

RegDesk is a next-generation web-based software for medical device and IVD companies. Our cutting-edge platform uses machine learning to provide regulatory intelligence, application preparation, submission, and approvals management globally. Our clients also have access to our network of over 4000 compliance experts worldwide to obtain verification on critical questions. Applications that normally take 6 months to prepare can now be prepared within 6 days using RegDesk Dash(TM). Global expansion has never been this simple.