Process validation should normally be completed prior to the distribution of any tissue or cell (prospective validation). In exceptional circumstances, where this is not possible, it may be necessary to validate processes during routine production (concurrent validation). Processes in use for some time should also be validated (retrospective validation).
Facilities, systems and equipment to be used should have been qualified and analytical testing methods should be validated. Staff taking part in the validation work should have been appropriately trained.
Facilities, systems, equipment and processes should be periodically evaluated to verify that they are still operating in a valid manner.