ASTM E 1714 is a Standard Guide for Properties of a Universal Healthcare Identifier (UHID). This standard was create by the Association for Information and Image Management and ASTM International. It defines thirty characteristics required of a UHID. The scope of the guide does not include implementation methodology, cost, or policy decisions. Encrypted UHIDs (EUHIDs) are included in the guide for hiding the identity of individuals while linking information. Separate EUHIDs are allowed for different episodes of care for the same patient. The guide also recommends the use of temporary patient identifiers (TPIs) controlled by individual organizations for emergency use and requires them to subsequently transfer all information to the correct UHID.