Anyone know anything about HL7 ?

James Huffman · Sep 2, 2004

Maybe this will help.

Jim Huffman

HL7 in the 21st Century

Integrating medical information exchange

April 2000 - Healthcare Informatics

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BETTER KNOWN AS HL7, Health Level Seven is both an American National Standards Institute (ANSI)-accredited standards organization and a standard. The organization, founded in 1987 with an

original committee of 14 people, now numbers nearly 2,000 members including healthcare providers, vendors and consultants.

As a standards development organization, HL7's mission is to provide standards for the exchange, management and integration of data that support clinical patient care, and the management and delivery of healthcare services by defining the protocol for exchanging clinical data between diverse healthcare information systems. The HL7 organization works through volunteer efforts to create flexible, cost-effective approaches, standards, guidelines, methodologies and related services for interoperability between healthcare information systems.

As a standard, HL7 is widely accepted and used. Since its creation, this standard has grown from a user-based consensus standard to an international standard with affiliate groups in Australia, Canada, Finland, Germany, India, The Netherlands, New Zealand, South Africa and the United Kingdom. Named as the most widely used standard among healthcare providers in a 1998 survey of 153 CIOs sponsored by the College of Healthcare Information Management Executives (CHIME) and HCIA Inc., HL7 has cut costs and facilitated interconnectivity.

In 1999, two HL7 protocols were published in an effort to move HL7 beyond its traditional message-based functionality.

First, the HL7 organization published the Clinical Context Management Specification Version 1.0 (CCM) as an ANSI standard. Previously known as CCOW, but now represented by HL7's Special Interest Group for Visual Integration, the CCM standard establishes nationwide support for the visual integration of disparate healthcare applications on the clinical desktop. Vendors supporting this standard enable end users to seamlessly view results from different back-end clinical systems as if they were totally integrated.

Also, the HL7 Arden Syntax for Medical Logic Systems Version 2.0 was approved as an American National Standard. The Arden Syntax, a language used for encoding medical decision making into health knowledge bases, can be used to encode clinical reminders, alerts, interpretations and diagnoses.

Reduce time and effort

Since the publication and widespread implementation of HL7 version 2.1 in 1990, use of the standard has slashed interface costs by specifying the meaning of events that trigger information flows and the definition of the data fields that flow between systems. Custom-built interfaces prior to the introduction of the HL7 standard can cost between $50,000 and $250,000. Today, an HL7 interface with similar functionality costs between $2,000 and $10,000.

Savings in time and effort to install HL7 interfaces are equally dramatic. An HL7 interface usually requires a fraction of the amount of work to write a proprietary interface. An interface analyst can complete HL7 interface connections in a matter of hours.

Although a significant number of systems still need to be interconnected, it is not necessary to connect every system with all the others. The graph on the next page shows the amount of work vs. the number of systems that need to be connected. The amount of work required for all the systems to be interconnected without using HL7 (purple line) grows arithmetically and quickly balloons out of control as the number of systems increases. The conventional and desirable amount of interconnectedness within a hospital (red line) shows that beyond 10 systems the amount of work is prohibitive. At this point, hospitals begin to consider using HL7 and interface engine technology to reduce maintenance headaches.

Although HL7 version 2.X commonly specifies the majority of the interface information without difficulties, parts of HL7 2.X are too permissive and allow interpretive wobbles in the standard. Despite this inherent "wobble," which is exacerbated by the absence of standard medical vocabularies and nonstandardized work processes, HL7 still drastically reduces the implementation time and the amount of work required to connect many diverse systems. For simple registration and financial transactions, organizations can expect to eliminate 93 percent of interface development time. Complex orders and results work can be cut 82 percent.

An interface engine further reduces the amount of work required to connect systems. Although there is a significant reduction in work (blue line) using just an interface engine to connect every system (without using HL7), HL7 further cuts the work involved (green line). Although the cost savings possible for healthcare organizations with few interconnected systems is small, use of both HL7 standards and interface engine technology can produce huge savings for complex, multivendor environments.

This potential has not been lost among large hospitals. A 1998 survey found the HL7 standard in use in more than 95 percent of hospitals with more than 400 beds. Overall, more than 80 percent of the respondents in that study reported using HL7 in their IS departments with another 13.5 percent planning to do so.

The current version, HL7 2.3.1, has established itself as a nearly universal standard for clinical and administrative data. Even as version 2.4, currently in draft, will further extend the functionality of health data exchange, the HL7 group is positioning itself to take major steps toward expanding the uses of HL7 integration.

HL7 XML

HL7 will gain important functionality with the next major release, version 3.0, which will further expand the capabilities of medical information exchange. One of the new aspects in this next version is the evolution of information encoding. Although HL7 has supported a loosely coupled business-to-business protocol for more than a decade, version 3.0 adds an encoding definition for an application layer protocol for healthcare information by using native extensible markup language (XML) to describe the grammar or syntax of the language of healthcare and define it with information tags. Replacement of traditional HL7 position-based encoding will be straightforward and is expected to move the HL7 standards model to a new level. HL7 versions 3.0 and higher could be nicknamed "HL7 XML."

In recent years, HL7 has grown to be much more than the clinical messaging for which it was originally developed. XML technology offers users of the HL7 standard a plethora of additional possibilities to tighten medical interface specifications and expand data exchange possibilities. XML functionality will extend HL7 to support both HL7 messages and HL7 document encoding. The strengths of XML allow users to write a tagged document once but use it in various ways to give an HL7 XML document extended life beyond that of the Internet and a traditional HL7 message. HL7 XML documents--representing stored database information--can transfer information between different databases.

XML's vendor-neutral data architecture makes HL7 XML encoding a perfect medium in which to design a vendor-neutral standard to represent clinical data in the medical record and facilitate the exchange of clinical information at minimal expense. In HL7 XML, everything from a patient's online medical record to a pharmacy's formulary could be represented and exchanged in an HL7 XML document. HL7's Patient Record Architecture in version 3.0 will allow a standard format for exchanging a patient's medical records between different hospital systems or even different hospitals. Scheduled for publication in 2001, the HL7 3.0 standard has been planned and developed to serve as a foundation for the universal electronic medical record.

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David John Marotta is cochair of the Health Level Seven Education and Implementation Subcommittee and president of DT7 Software, LLC in Charlottesville, Va.

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Mariah · Sep 2, 2004

check out http://www.hl7.org for full information