In my company, typically for testing our implants we follow an FDA guidance document that details the recommended tests for that type of device, and we submit this test data with our 510k submissions. However, sometimes we feel that additional tests are necessary which are not recommended or required by the FDA, or sometimes upon review of our 510k submission the FDA will ask for additional test data that was not mentioned in the guidance document. For our instrumentation used in conjunction with our implant system, however, there are no standardized tests and no guidance documents that we follow. This is strictly up to the engineers to define these tests to make sure the design of the instruments is robust.