It is not feasible economically nor justifiable in practice to subject all medical devices to the most rigorous conformity assessment procedures available. A graduated system of control is more appropriate. In such a system, the level of control corresponds to the level of potential hazard inherent in the type of device concerned. A medical device classification system is therefore needed, in order to apply to medical devices an appropriate conformity assessment procedure.
The classification of medical devices is a ‘risk based’ system based on the vulnerability of the human body taking account of the potential risks associated with the devices. This approach allows the use of a set of criteria that can be combined in various ways in order to determine classification, e.g. duration of contact with the body, degree of invasiveness and local vs. systemic effect.
According to the ISO 62304 Section 4.3 it is being said:
Software safety classification shall be done in accordance to the following guidance:
a) The MANUFACTURER shall assign to each SOFTWARE SYSTEM a software safety class (A, B, or C) according to the possible effects on the patient, operator, or other people resulting from a HAZARD to which the SOFTWARE SYSTEM can contribute. The software safety classes shall initially be assigned based on severity as follows:
Class A: No injury or damage to health is possible
Class B: Non-SERIOUS INJURY is possible
Class C: Death or SERIOUS INJURY is possible
If the HAZARD could arise from a failure of the SOFTWARE SYSTEM to behave as specified, the
probability of such failure shall be assumed to be 100 percent. If the RISK of death or SERIOUS INJURY arising from a software failure is subsequently reduced to an acceptable level (as defined by ISO 14971) by a hardware RISK CONTROL measure, either by reducing the consequences of the failure or by reducing the probability of death or SERIOUS INJURY arising from that failure, the software safety classification may be reduced from C to B; and if the RISK of non-SERIOUS INJURY arising from a software failure is similarly reduced to an acceptable level by a hardware RISK CONTROL measure, the software safety classification may be reduced from B to A.
Where the Lines Blur
For more than 90% of products, classification is very clear. Still, certain products cause confusion, and what may seem like an ordinary device might be considered a medical device or a drug (or combination, such as a drug-eluting stent) depending on claims and how it is used.
In conclusion, the first regulatory step toward European device compliance is to determine whether your device is considered to be a device and, if so, what the classification will be for Europe. You simply cannot let this determination be based on the US classification of your device.