Your external power supply - is it a power supply or a battery charger? If it is a power supply your device would have no function with out it, so it would have to be considered as part of the device. Perhaps even, it might not perform it's medical purpose whilst charging.
If labeling, promotional materials, or other evidence of intended use demonstrates that the device is intended to support, supplement, and/or augment another device, whether a particular brand or a device type, that device is considered an accessory. For example, an infusion pump system may include an infusion pump and a stand.
What does accessory mean?
IV. Definitions Accessory: A finished device that is intended to support, supplement, and/or augment the performance of one or more parent devices.
What is the difference between accessory and component?
Definitions Accessory: A finished device that is intended to support, supplement, and/or augment the performance of one or more parent devices. Component (21 CFR 820.3(c)): “ny raw material, substance, piece, part, software, firmware, labeling, or assembly which is intended to be included as part of the finished, packaged, and labeled device.”
The battery example is now absent from the final guidance, and the final guidance states: “non-device-specific off-the-shelf replacement parts (e.g., batteries, USB cables, computer mouse, etc.) may be used with a medical device, but FDA does not intend to consider these products to be accessories or medical devices.”
It is important to note that articles that do not meet the definition of an accessory will not be treated as accessories simply because they may be used in conjunction with a device. For example, a mobile smart phone would not be considered an accessory after having downloaded a medical application (app).
Is analyzing data from a device considered an accessory?
Although analyzing data from a device would not result in the software being deemed an accessory, the guidance states that software that may be used in combination with other devices may be considered an accessory.