Founded in 1987, Health Level Seven International (HL7) is a nonprofit, ANSI-accredited standards-developing organization that provides a framework (and related standards) for the exchange, integration, sharing, and retrieval of electronic health information. These tools support clinical practice and the management, delivery, and evaluation of health services.

There are 382 organizational members in HL7. Members include affiliates; benefactors; consultants; government and universities; payers; pharmaceuticals; providers; and suppliers and vendors).

As defined in ISO/IEC Guide 2:1996A, a standard is a document, established by consensus, that provides rules, guidelines, or characteristics for activities or their results.  Standards define how information is packaged and communicated from one party to another. These set the language, structure, and data types required for seamless integration between systems.

The name (HL7) 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 standards are grouped into reference categories:

• Section 1: Primary Standards - Integral for system integrations, interoperability, and compliance.
• Section 1a: Clinical Document Architecture (CDA®) - Clinical Document Architecture (CDA®) Products
• Section 1b: EHR - Electronic Health Records - Functional models and profiles that enable the constructs for management of electronic health records.
• Section 1c: FHIR® - FHIR® – Fast Healthcare Interoperability Resources
• Section 1d: Version 2 (V2) - Version 2 (V2)
• Section 1e: Version 3 (V3) - HL7 Version 3 (V3) - Suite of specifications based on HL7's Reference Information Model (RIM)
• Section 1f: Arden Syntax - Representing procedural clinical knowledge to facilitate sharing of computerized health knowledge bases among personnel, information systems, and institutions
• Section 1g:  Clinical Context Management Specification (CCOW) - Facilitating integration of applications at the point of use (standard for internal applications programming and runtime environment infrastructure to complement HL7's traditional emphasis on data interchange and enterprise workflow).
• Section 1h: Cross-paradigm/Domain Analysis Models - Cross-paradigm/ Logical Level Standards e.g. Domain Analysis Models
• Section 2: Clinical and Administrative Domains - Messaging and document standards for clinical specialties and groups.
• Section 3: Implementation Guides - Documents created to be used in conjunction with an existing standard.
• Section 4: Rules and References - Technical specifications, programming structures, and guidelines for software and standards development.