Health Level 7

Health Level Seven, Inc. (HL7), is an all-volunteer, not-for-profit organization involved in development of international healthcare standards. “HL7” is also used to refer to some of the specific standards created by the organization (i.e. HL7 v2.x, v3.0, HL7 RIM etc.).

HL7's Mission HL7 is an international community of healthcare subject matter experts and information scientists collaborating to create standards for the exchange, management and integration of electronic healthcare information. HL7 promotes the use of such standards within and among healthcare organizations to increase the effectiveness and efficiency of healthcare delivery for the benefit of all.

HL7's Strategies: Develop coherent, extendible standards that permit structured, encoded health care information of the type required to support patient care, to be exchanged between computer applications while preserving meaning. Develop a formal methodology to support the creation of HL7 standards from the HL7 Reference Information Model (RIM). Educate the healthcare industry, policy makers, and the general public concerning the benefits of healthcare information standardization generally and HL7 standards specifically. Promote the use of HL7 standards world-wide through the creation of HL7 International Affiliate organizations, which participate in developing HL7 standards and which localize HL7 standards as required. Stimulate, encourage and facilitate domain experts from healthcare industry stakeholder organizations to participate in HL7 to develop healthcare information standards in their area of expertise. Collaborate with other standards development organizations and national and international sanctioning bodies (e.g. ANSI and ISO), in both the healthcare and information infrastructure domains to promote the use of supportive and compatible standards. Collaborate with healthcare information technology users to ensure that HL7 standards meet real-world requirements, and that appropriate standards development efforts are initiated by HL7 to meet emergent requirements.

Headquartered in Ann Arbor, Michigan, U.S., Health Level Seven is a standards organization that is accredited by the American National Standards Institute (ANSI). HL7 was founded in 1987 to produce a standard for hospital information systems. HL7 and its members provide a framework (and related standards) for the exchange, integration, sharing and retrieval of electronic health information. The standards, which support clinical practice and the management, delivery, and evaluation of health services, are the most commonly used in the world.

Overview
Hospitals typically have many different computer systems used for everything from billing records to patient tracking. All of these systems should communicate with each other (or "interface") when they receive new information but not all do so. HL7 is a language by which various healthcare systems can do this.

Background and organizational structure
The HL7 organization develops standards designed to increase the effectiveness, efficiency and quality of healthcare delivery. The organization is managed by a Board of Directors, which comprises eight elected positions and three appointed positions. Members of Health Level Seven are known collectively as “The Working Group”. The Working Group is responsible for defining the HL7 standard protocol and is composed of Standing Administrative Committees, Special Interest Groups, and Technical Committees.

Standing Administrative committees focus on organizational or promotional activities, such as Education, Implementation, Marketing, Outreach Committee for Clinical Research, Publishing and Performance Improvement and Tooling.

Special interest groups serve as a test bed for exploring new areas that may need coverage in HL7’s published standards, such as Clinical Genomics, Clinical Guidelines, Community Based Health Services, etc.

Technical committees are directly responsible for the content of the Standards, framing the actual language of the specifications.

Focus
A frequent misconception about HL7 is that the group develops software. In fact, HL7’s primary mission is to create flexible standards, guidelines, and methodologies to enable the exchange and interoperability of electronic health records. Such guidelines or data standards are a set of rules that allow information to be shared and processed in a uniform and consistent manner. These data standards are meant to allow healthcare organizations to easily share clinical information. Theoretically, this ability to exchange information should help to minimize the tendency for medical care to be geographically isolated and highly variable. Access to the HL7 standards requires paid membership, which ranges from US$125 for an individual up to US$34,000 for organizations with the cost depending on annual health-care revenue and benefactor or supporter status.

Most Standards Developing Organizations (SDOs), including Health Level Seven, produce standards (sometimes called specifications or protocols) for a particular healthcare domain such as pharmacy, medical devices, imaging or insurance (claims processing) transactions. Health Level Seven’s domain is clinical and administrative data. HL7 develops Conceptual Standards (i.e. HL7 RIM), Document Standards (i.e. HL7 CDA), Application Standards (i.e. HL7 CCOW) and Messaging Standards (i.e. HL7 v2.x and v3.0).

Messaging standards are particularly important because they define how information is packaged and communicated from one party to another. Such standards set the language, structure and data types required for seamless integration from one system to another. Currently, HL7’s messaging standard is supported by every major medical information systems vendor in the United States.

Areas of interest
In 1994, HL7 became accredited by ANSI.

In the years since its founding, HL7 has expanded its influence well beyond traditional messaging protocols. Today HL7 standards development initiatives include the following:
 * standardization of knowledge representation (Arden syntax)
 * specification of components for context management (known as CCOW)
 * support for healthcare data interchange using object request brokers
 * extend interoperability for the development of Health Information Exchange
 * standardization of XML document structures
 * specification of robust vocabulary definitions for use in clinical messages and documents (cf. SNOMED CT, LOINC)
 * functional specifications for an electronic health record
 * work in the area of security, privacy, confidentiality, and accountability.

Such innovation has allowed for everything from the availability of a patient's online medical record to a pharmacy's formulary to be represented and exchanged in an HL7 XML document. The HL7's Patient Record Architecture in (message standard) version 3.0 allows for a common format for exchanging a patient's medical record between different hospital systems or even different hospitals. This HL7 standard has come to serve as a foundation for the universal electronic medical record.

The scope of HL7’s activities is not limited to the electronic medical record, however. Recent activities and standards of HL7 have included modeling and methodology, vocabulary, clinical decision support, financial management, administration, regulated clinical research and information management, scheduling and logistics, clinical guidelines, community-based health, government projects, medication, security and accountability, templates, XML, and public health and emergency response.

HL7 has allowed for the interoperability between electronic Patient Administration Systems (PAS), Electronic Practice Management (EPM) systems, Laboratory Information Systems (LIS), Dietary, Pharmacy and Billing systems as well as Electronic Medical Record (EMR) or Electronic Health Record (EHR) systems. HL7 encompasses the complete life cycle of a standards specification including the development, adoption, market recognition, utilization, and adherence.

Stated goals of HL7

 * Develop coherent, extendable standards that permit structured, encoded health care information of the type required to support patient care, to be exchanged between computer applications while preserving meaning.
 * Develop a formal methodology to support the creation of HL7 standards from the HL7 Reference Information Model (RIM).
 * Educate the healthcare industry, policy makers, and the general public concerning the benefits of healthcare information standardization generally and HL7 standards specifically.
 * Promote the use of HL7 standards world-wide through the creation of HL7 International Affiliate organizations, which participate in developing HL7 standards and which localize HL7 standards as required.
 * Stimulate, encourage and facilitate domain experts from healthcare industry stakeholder organizations to participate in HL7 to develop healthcare information standards in their area of expertise.
 * Collaborate with other standards development organizations and national and international sanctioning bodies (e.g. ANSI and ISO), in both the healthcare and information infrastructure domains to promote the use of supportive and compatible standards.
 * Collaborate with healthcare information technology users to ensure that HL7 standards meet real-world requirements, and that appropriate standards development efforts are initiated by HL7 to meet emergent requirements.

Involvement with HIPAA
HL7’s initial involvement in the Health Insurance Portability and Accountability Act (HIPAA) legislation began in 1996 with the formation of the Attachments special interest group to standardize the supplemental information needed to support health care insurance, and other e-commerce transactions. The initial deliverable of this group was six recommended Claims Attachments for the Notice of Proposed Rule Making (NPRM) process. Future attachment projects include, but are not limited to, Home Health, Skilled Nursing Facility, durable medical equipment (DME), end stage renal disease (ESRD), and Pre-Authorization and Referrals. The Attachment special interest group has the responsibility for the implementation of the Administrative Simplification provisions of HIPAA mandates, providing on-going support, and representing HL7 in the HIPAA Designated Standards Maintenance Organization (DSMO)efforts. Its purpose is to encourage the use of HL7 for uniform implementation of this supplemental information. This SIG coordinates industry input to produce and maintain guides for HL7 messages that can stand alone or be embedded within ASC X12N transactions.

Version 3
HL7 Version 3 is a HL7 messaging standard thus far. Version 3 uses a Reference Information Model (RIM; see below) as a common source for the information content of specifications.

As part of Version 3, the HL7 Vocabulary Technical Committee developed methods that allow HL7 specifications to draw upon codes and vocabularies from a variety of sources. The V3 vocabulary work assures that the systems implementing HL7 specifications have an unambiguous understanding of the code sources and code value domains they are using.

The HL7 Version 3 development methodology is a continuously evolving process that seeks to develop specifications that facilitate interoperability between healthcare systems. The HL7 RIM, vocabulary specifications, and model-driven process of analysis and design combine to make HL7 Version 3 one methodology for development of consensus-based standards for healthcare information system interoperability. The HDF is the most current rendition of the HL7 V3 development methodology.

External white paper with discussions of HL7 version 3.X and HL7 version 2.X: The HL7 Evolution: Comparing HL7 Version 2 to Version 3, Including a History of Version 2

A large portion of HL7 messaging is transported by MLLP.

Reference Information Model (RIM)
The Reference Information Model (RIM) is the cornerstone of the HL7 Version 3 development process and an essential part of the HL7 V3 development methodology. RIM expresses the data content needed in a specific clinical or administrative context and provides an explicit representation of the semantic and lexical connections that exist between the information carried in the fields of HL7 messages. The RIM is essential to increasing precision and reducing implementation costs. Models are available.

HL7 Development Framework (HDF)
The HDF documents the processes, tools, actors, rules, and artifacts relevant to development of all HL7 standard specifications, not just messaging. This initial version of the HDF methodology specification will address updates to messaging specification, and will be applicable to structured documents and context management. Eventually, the HDF will encompass all of the HL7 standard specifications, including any new standards resulting from analysis of electronic health record architectures and requirements.

Arden syntax
The Arden syntax is a language for encoding medical knowledge. HL7 adopted and oversees the standard beginning with Arden syntax 2.0. These Medical Logic Modules (MLMs) are used in the clinical setting as they can contain sufficient knowledge to make single medical decisions. They can produce alerts, diagnoses, interpretations, and contain a quality assurance function and administrative support. An MLM must be run on a computer that meets the minimum system requirements and has the correct program installed. Once this is provided, the MLM can give advice when and where it is needed.

Special projects
The Health Level Seven group joined forces with the Electronic Health Record Vendors Association (EHRVA) to assist patients in the aftermath of Hurricane Katrina. With the single largest pool of expertise in connecting healthcare information systems, these groups are actively working on activities with local, state wide and national agencies (including the DHHSand the CDC) to provide solutions for those in the affected area.

Critical reviews

 * HL7 Watch (weblog) - see also the posted comments for rebuttals to some of the critical theses advanced.
 * HL7 RIM: An Incoherent Standard, a paper by Barry Smith, now published in Studies in Health Technology and Informatics, vol. 124, 133–138 (the proceedings of the Medical Informatics Europe 2006 Conference held in Maastricht, Holland - August 27-August 30 2006). Also see Smith's slideshow presented at the Maastricht conference.
 * The HL7 RIM Under Scrutiny, Rebuttal to Smith's paper by Gunther Schadow, presented at the same Medical Informatics Europe 2006 conference. Also see the Animated Slideshow presented at the conference.
 * Panel on the Future of HL7 held at the 2006 Annual Symposium of the American Medical Informatics Association in Washington DC.

Open source tools
There are a number of OSS based tools that can foster worldwide adoption of the HL7 standards


 * The Perl HL7 Toolkit, an Open-Source HL7 Perl module
 * The Mirth Project, a java based OSS HL7 interface engine
 * HAPI, An open-source, object-oriented HL7 2.x parser for Java
 * Pear (PHP) HL7 messaging API module
 * The eXcessively Simple HL7 v2 Processing Platform using XML and XSLT
 * The HL7 Java Special Interest Group's implementation of HL7 v3
 * The Ruby HL7 Library
 * HL7 Java binding

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