Health Level 7



What is Health Level 7 (HL7)?

“HL7” is a term used to refer to the all-volunteer, not-for-profit organization, Health Level Seven, Inc., that is 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.).

Headquartered in Ann Arbor, MI, Health Level Seven is a Standards Developing Organization (SDO) that is accredited by the American National Standards Institute (ANSI). Founded in 1987 to produce a standard for hospital information systems, HL7 is currently the selected standard for the interfacing of clinical data in most institutions. HL7 and its members are dedicated to providing a comprehensive 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.

HL7 has saved time, effort, and money as institutions attempt to interface. According to David John Marotta, cochair of the Health Level Seven Education and Implementation Subcommittee, custom-built interfaces - prior to the introduction of the HL7 standard - cost between $50,000 and $250,000. In 2000 the expense of an HL7 interface with similar functionality ranges between $2,000 and $10,000. Savings in time and effort to install HL7 interfaces are equally dramatic. An interface analyst can complete HL7 interface connections in a matter of hours. Previous versions of the HL7 V2.x standards are available free of charge while current standards may be purchased at a modest fee.

Background and Organizational Structure

The HL7 organization has grown from a modest 14 members in 1987, to over 2200 members worldwide including 500 corporate members today, which includes International Affiliates in 33 countries. These members share a commitment to the development and advancement of clinical and administrative standards in healthcare. Using a well-defined set of operating procedures, HL7’s members – including vendors, providers, consultants and payers - have information technology expertise in all segments of the healthcare industry. Collectively, they develop the standards designed to increase the effectiveness, efficiency and quality of healthcare delivery. The organization is managed by a Board of Directors, which is comprised of 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 comprised 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.

HL7’s Focus

A frequent misconception about HL7 is that the group develops software. In fact, HL7’s primary mission is to create flexible, low-cost standards, guidelines, and methodologies to enable the exchange and interoperability of electronic health records. Such guidelines or data standards are an agreed upon set of rules that allow information to be shared and processed in a uniform and consistent manner. Without data standards, healthcare organizations could not readily share clinical information. Theoretically, this ability to exchange information should help to minimize the tendency for medical care to be so geographically isolated and highly variable.

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. Interestingly, HL7, Inc. 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:
 * standardization of knowledge representation (Arden Syntax)
 * specification of components for context management (known as CCOW)
 * support for healthcare data interchange using object request brokers
 * standardization of XML document structures
 * specification of robust vocabulary definitions for use in clinical messages and documents
 * 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. In fact, 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 thus come to serve as a foundation for the universal electronic medical record.

The scope of HL7’s progressive activities is not limited to the electronic medical record, however. Indeed, 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.

The specific goals of the HL7 are to:


 * 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.

HL7’s involvement with HIPAA

HL7’s initial involvement in the 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.

What is Version 3?

HL7 Version 3 is the most definitive HL7 messaging standard thus far, incorporating more trigger events and message formats than any previous version. 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 an exemplary 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.

How is Version 3 different from previous versions?

Health Level Seven’s Version 3 strives to improve the V2 process and its outcomes. New capabilities offered in Version 3 include:
 * Top-down message development emphasizing reuse across multiple contexts and semantic interoperability;
 * Representation of complex relationships;
 * Formalisms for vocabulary support;
 * Support for large scale integration;
 * Solving re-use and interoperability across multiple domain contexts;
 * A uniform set of models;
 * Expanded scope to include community medicine, epidemiology, veterinary medicine, clinical genomics, security, etc.

What is the 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.

What is the 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.

What is 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 very useful in the clinical setting as they can contain sufficient knowledge to make single medical decisions. Not only can MLMs produce alerts, diagnoses, interpretations, they also contain a quality assurance function and administrative support. The user must provide enough memory and the correct computer program for the MLM to run. Once this is provided, the MLM can give advice when and where it is needed.

HL7 Special Projects

Recently, the Health Level Seven group has 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, statewide and national agencies (including the DHHSand the CDC) to provide solutions for those in the affected area.