Tutorials, W. Rishel Research Note 26 November 2002 Building Better Interfaces: HL7 Conformance Profiles The new Health Level Seven conformance technology allows individual healthcare organizations and vendors to specify and negotiate HL7 interfaces more precisely. It will also improve conformance testing. Core Topic Healthcare: Healthcare Technologies, Infrastructure and Standards Key Issue Within the next 10 years, which future developments in Information technologies, standards and regulations are most likely to significantly impact the healthcare industry? Strategic Planning Assumption By February 2004, when the Health Information Management Systems Society trade show takes place, at least five wellknown tool and application vendors will be showing the ability to import and export HL7 message profiles (0.8 probability). Key Facts: HL7 message profiles are XML documents that constitute implementation specifications for HL7 interfaces. HL7 message profiles can build on one another, greatly simplifying the job of creating a complex set of specifications. Freeware and commercial tooling is already available to support use of HL7 message profiles. Health Level Seven (HL7) message specifications have many options, enabling individual healthcare organizations (HCOs) to adapt them to their internal needs. When these standards are implemented, analysts must work with vendors and internal system developers to develop an implementation specification that prescribes specific treatment for all options. These implementation specifications are typically listed in word processing or spreadsheet documents. Everyone implementing a specification reads this document and manually configures or programs the relevant systems. Large enterprises frequently have hundreds of interface specifications. Usually, the specifications have many common features, but enough individual variations to mandate a separate specification. Maintaining all these specifications is a nightmare for both large vendors with multiple products in their catalogs and HCOs with multiple products installed. HL7 conformance technology will help deal with this problem. Since 1998, the HL7 Conformance Special Interest Group has been addressing the issues of describing and measuring conformance to implementation specifications for Version 2 messages. It has created a standard way to describe implementation specifications in Extensible Markup Language (XML). This is undergoing ballot as part of version 2.5 and will be certified by the American National Standards Institute during the first half of 2003. Some consultancies and large enterprises are already using the approach and find it improves analyst productivity and the completeness of their interface specifications. The conceptual heart of this approach is a "message profile." A message profile starts with a standard HL7 message Gartner Entire contents 2002 Gartner, Inc. All rights reserved. Reproduction of this publication in any form without prior written permission is forbidden. The information contained herein has been obtained from sources believed to be reliable. Gartner disclaims all warranties as to the accuracy, completeness or adequacy of such information. Gartner shall have no liability for errors, omissions or inadequacies in the information contained herein or for interpretations thereof. The reader assumes sole responsibility for the selection of these materials to achieve its intended results. The opinions expressed herein are subject to change without notice.
specification and describes constraints and additions to the message. Constraints Constraints limit which fields are used, and the contents of the fields in use. A constraint might specify that a patient identifier in a lab result message (optional under HL7) must be present and, furthermore, that it must be the institution's medical record number. Alternatively, an institution that does not use primary nursing might specify that in all patient demographics messages, the primary nurse field will always be empty. Constraints can even eliminate entire optional segments or groups of segments, or restrict the values within a field or subcomponent of a field. It could say that the code that identifies a test must be from the standard Logical Observation Identifiers, Names and Codes or that the secondary patient identifier must be sent, if it is known by the sending systems. Additions Note 1 Z-Segments Segments of HL7 messages with names that begin with the letter Z are specifically reserved for use by individual implementers to provide information not carried in the segments named by HL7. Additions support the common practice of adding "Z-segments" to transfer information not covered by the standard (see Note 1). They can specify additional segments, groups of segments that may repeat, fields within segments and subcomponents of the fields. Attacking the Maintenance Problem A message profile need not be based on a standard message. Instead, it can be based on another message profile. Using this approach, a large HCO can create general message profiles that specify most of their policies when using HL7 messages, and then derive specific variants for specific situations. For example, an HCO might have a general profile based on the HL7 Admit Patient message. This would describe the common features for all its admission, discharge and transfer systems. It can then copy this common information into multiple specific profiles that describe the outputs of the products in its various service areas. HL7 uses the term, "implementable profile" to describe a message profile that has fully constrained the root HL7 message, so that no optionality remains. Until a chain of message profiles reaches the state of being fully constrained, it cannot serve as the basis of an interoperable interface. Analysts will have to create additional message profiles to eliminate the remaining optionality. 26 November 2002 2
XML to Convey Metadata The new standard way of describing a message profile is an XML document that conforms to a specific, HL7-produced schema. Until now, HL7 has used XML to send data between applications. The new HL7 schema uses XML to communicate metadata data about data. Compared to word processing and spreadsheets, this is a big step forward. XML can be transformed into HTML or Portable Document Format (PDF) files simply. These are easily interpreted by users. Indeed, early adopters of this technology have told Gartner that they use multiple transformations from the same basic XML document to achieve different levels of detail for different audiences. Maintaining such multiple documents using word processing or spreadsheets would be extremely timeconsuming and error-prone. The XML can be just as easily imported by software tools to reduce errors and simplify the task of configuring software to match the specifications. Gartner already knows of three tools that import and export HL7 message profiles: the freeware Messaging Work Bench (MWB) available by download from www.hl7.org; Symphonia v.3.6 from Orion Systems International; and the Medi7 Parser Toolkit from Eversolve. Comparing and Sharing Profiles HL7 message profiles can be compared using software tools. As HCOs and vendors produce standard message profiles for their requirements and products, comparison tools will facilitate very precise analysis of issues that must be negotiated to install or upgrade a product. HL7 has created a repository for message profiles on www.hl7.org. Enterprises can post their profiles and browse others' postings. HL7 hopes that an analyst preparing a new specification will check the Web site and reuse or adapt profiles that already exist, rather than reinventing a new solution. Initially, most vendors will be reluctant to post their message profiles publicly, even if they are providing them directly to clients under nondisclosure. This could change if enough users bring pressure on the vendors to make public postings. Even without vendor contributions, the contributions from user sites could create a rich library of specifications. 26 November 2002 3
Value of HL7 Message Profiles in 2002 The MWB was developed by Peter Rontey of the Veteran's Health Administration. He affirms its productivity benefits and maintains a large library of interface specifications. Gartner has talked to several consultancies that routinely use the MWB to create written specifications for specific implementations. They are reporting that they can prepare implementation specifications more quickly, with more confidence in their completeness, than was the case without this technology and tool. They also use the MWB to automate the generation of sample messages and test data, two tasks that are otherwise extremely tedious. IBM is using HL7 message profiles in a large project in Canada. In this case, the analyst has chosen not to use the MWB and is using XMLSpy and other tools to maintain the message profiles directly. McKesson Information Systems is converting its internal tooling for HL7 interfaces to support HL7 message profiles and has an arrangement with Orion Systems International to offer its clients a free version of the Symphonia EDI Message Designer. Because the message profiles are in a standard format, their clients are not obliged to use Symphonia. Future Value as HL7 Message Profiles Gather Momentum Gartner has talked to a very large, integrated delivery system that is evaluating revising their internal methodologies to use HL7 message profiles. It perceives substantial value of the new methodology but will have to invest in overcoming inertia because it already has a large body of specifications. The benefits of HL7 message profiles will grow exponentially when more tools and applications are built to accept and produce HL7 message profiles and to provide analytic services, such as those offered by the MWB. The Australian Health Messaging Laboratory, which offers an online testing service for HL7 messages, intends to allow users to submit HL7 message profiles to create testing services. In the United States, the National Institute of Standards and Technology is considering developing freeware HL7 testing suites, driven by HL7 message profiles. During 2003, we believe that the publication of message profiles as a standard in version 2.5 will make it easier for large enterprises and vendors to adopt this approach. By February 26 November 2002 4
2004, when the Health Information Management Systems Society trade show takes place, at least five well-known tool and application vendors will be showing the ability to import and export HL7 message profiles (0.8 probability). Acronym Key HCO Healthcare organization HL7 Health Level Seven MWB Messaging Workbench XML Extensible Markup Language Bottom Line: Health Level Seven (HL7) message profiles have an exciting future as they gather momentum. The methodology, schema and tooling already available enable healthcare organizations (HCOs) to achieve immediate productivity gains. Vendors should start to use the technology to maintain their interface specifications. HCOs should do the same, and use new contract negotiations with vendors as a lever to insist that vendors use HL7 conformance technology to describe their proposed and final delivered interfaces. All enterprises should check the HL7 repository when developing new specifications and contribute specifications for established software to it. 26 November 2002 5