Health Level Seven (HL7) is an American National Standards Institute (ANSI) standard messaging protocol that specifies the set of transactions and encoding rules for electronic data exchange between health care computer systems. HL7 provides an open, standards-based framework that computer systems can use to exchange health care data with each other. The HL7standards development group is directly focused on health care informatics standards and cooperates closely with developers of other standards.    (3RC4)

The VistA HL7 package enables M-based VistA applications running on core facility computer systems to exchange health care information with other computer systems. It provides messaging services and a single toolset for M-based VistA applications to create, send, receive, and process HL7 messages.    (3RC5)