Routes to the CE mark Since the general Directive concerning medical devices covers a very wide spectrum of products, it has not been considered appropriate to use same conformity assessment procedure for all medical devices. The Directive therefore divides the medical devices into four different classes (I, IIa, IIb and III). In addition, class I is subdivided into devices which are sold in a sterile condition and devices which are sold with a measuring function. The classification reflects the risks involved in the use of the product, the vulnerability of the parts of the body on which the devices are to be applied and the duration of use. The highest risk class (III) includes products which come into contact with the central nervous system, the heart or the central circulatory system as well as medical devices incorporating medicines. The classification thus ensures that the regulatory control is reasonably proportional to the risk involved in the use of the product. The following pages provide detailed descriptions of the different routes to CE marking from which the manufacturer can choose for the respective classes of medical devices. Routes to the CE mark for MDD In vitro diagnostic devices are also divided into four "classes". Annex II of the Directive comprises two lists: A (includes certain blood groupings and infections with HIV, HTLV and hepatitis viruses) and B (includes blood transfusions, infectious diseases, tumors and hereditary diseases.) Additionally, the Directive defines "devices for self-testing" (the use of a lay person in a home environment). Devices included on one of the two lists as well as devices for self-testing require the intervention of a notified body if they are to be marketed legally. This is due to the risk involved should the product not function according to its intended use. The manufacturer may market devices not mentioned above without the intervention of a notified body. The following pages provide detailed descriptions of the different routes to CE marking from which the manufacturer can choose for the respective classes of in vitro diagnostic devices. Routes to the CE mark for IVDD