Per personal experience to track the medical devices while it is on market, the company I work at has a technical support team that answers any immediate questions or complaints a user may have. Hopefully most of the time the issue is not serious and is resolved by technical support but the complaint is still logged. However, if the issue is a bit more serious which requires the device to be shipped backed and examined by our engineers an ER or Event Report is created. This ER contains the issue the user is experiencing with the device where the Engineer then has to figure out the cause, and if there is an issue in another device thus doing a verification with n sample size. The device goes through a full quality check and inspection before being shipped back out into the market. Additionally, in house testing occurs called integration testing whenever a new software is released for the device.