The Unique Device Identification (UDI) System is intended to assign a unique identifier to medical devices within the United States, Europe, China, South Korea, Saudi Arabia and Taiwan. It was signed into law in the US on September 27, 2007, as part of the Food and Drug Administration Amendments Act of 2007. The EU acted to adopt UDI and on April 5, 2017, under the EU Medical Device Regulation (MDR) and In-vitro Diagnostic Regulation (IVDR), but adoption has been postponed to 2021; see Medical Device Regulation.