EU Classification of Medical Devices Around the world, the definition of medical devices varies. Still, generally, a medical device is any instrument, equipment, machine, appliance, implant, reagent for in vitro use, software, material, or other similar or related product intended by the manufacturer to be used either alone or in combination for various medical purposes. Medical devices range from low-risk products such as thermometers to high-risk devices such as pacemakers. In the European Uni...