In Bipartisan Letter, Sens. Warren, Grassley Urge X12 Committee Finalize Its Unique Device Identifiers Recommendation for Medicare Claims Forms Targeted News Service (Press Releases) WASHINGTON, April 20, 2021: Chuck Grassley (R- Iowa) sent a letter to the Accredited Standards Committee (X12), the committee that sets industry standards for commonly used medical forms, urging them to finalize their recommendation that Medicare claims forms include the device identifier portion of a medical device's unique device identifier (UDI), which are serial numbers that are used to identify specific types of medical devices, including implantable devices like pacemakers or artificial joints. Their letter to X12 follows the senators'