The European Union defines Medical Device broadly, including any instrument, apparatus, appliance or even related software intended for the diagnosis, prevention, monitoring, treatment or alleviation of disease.
Falling under the Medical Device Directive (MDD; 93/42/EEC) are all of those devices not covered by more specific directives for In Vitro Diagnostics (IVD) or Active Implantable Medical Devices (AIMD).
The MDD is a complex document which outlines the essential requirements, classification rules and conformity routes for assessment of medical devices. Determining the specifics related to your device requires an understanding of the MDD's 23 articles, dozen annexes and 18 classification rules.
The assessment criteria and requirements depend on the risk level and complexity of the device, so manufacturers must determine whether their device is covered by the MDD or another directive (for example, the Active Implantable Medical Device Directive).
In the case of "Borderline" Products, which appear to be related to multiple directives, a positive determination is required. And certain products face more stringent requirements to ensure their safety. For example, Implantable items must have a Quality System that takes into account concerns of Biocompatibility and Sterilization.