Health Level Seven, or HL7, is an American National Standards Institute (ANSI) standard for healthcare specific data exchange between computer applications. "Level 7" refers to the seventh level of the International Organization for Standardization (ISO) seven-layer communications model for Open Systems Interconnection (OSI) - the application level. HL7 version 2.x (v.2.x) collectively defines a series of electronic messages to support administrative, logistical, financial as well as clinical processes. The v.2.x standards are backwards compatible, i.e. a message based on HL7 version 2.3 will be understood by an application that supports HL7 version 2.6.
