The HL7 Evolution
Comparing HL7 V2 to V3: Inluding a History of V2
Summary
HL7 Version 3 is released and available for use by the clinical application community. Medical informatists are already using it as a vocabulary to discuss worldwide healthcare issues. Government entities have begun to look forward to using it to create interfaces between systems that have previously been completely separate. Healthcare entities in Europe, Canada, Germany, and several others have launched initiatives to implement Version 3. Even with these activities, HL7 V3 is in the infant maturity stage while HL7 V2 is still growing in its usage
HL7 V3 addresses some of the problems inherent in HL7 V2 while creating a few new challenges. HL7 V3 builds upon much that was learned from the development of V2 but without the burden of the V2 legacy issues.
This article provides a background on HL7 and highlights the key differences between HL7 V3 and V2.
What is HL7?
HL7 is a Standards Developing Organization accredited by the American National Standards Institute to author consensus-based standards representing a broad view from healthcare system stakeholders.
What this definition means from a practical standpoint is that HL7 has compiled a collection of message formats and related clinical standards that loosely define an ideal presentation of clinical information, and together the standards provide a framework in which data may be exchanged.
The HL7 standard is often called the “non-standard standard.” While not entirely fair, it does reflect the fact that almost every hospital, clinic, imaging center, lab, and care facility is “special” and, therefore, there is no such thing as a standard business or clinical model for interacting with patients, clinical data, or related personnel.
Who uses HL7?
In order to set the context for both HL7 V2 and V3, it is critical to understand the user types for the messaging standards and how each user type influences both the development and use of the standard. Users can be divided into three segments:
Clinical interface specialists
who are tasked with moving clinical data, creating tools to move such data, or creating clinical applications that need to share or exchange data with other systems. These users are responsible for moving clinical data between applications or between healthcare providers.
Government or other politically homogeneous entities
that are looking to the future of sharing data across multiple entities or in future data movement – generally, few legacy systems are present. Often these users are looking to move clinical data in a new area not covered by current interfaces and have the ability to adopt or mandate a messaging standard.
Medical informatists
who work within the field of health informatics, which is the study of the logic of healthcare and how clinical knowledge is created. These users seek to create or adopt a clinical ontology – a sort of hierarchical structure of healthcare knowledge (a data model), terminology (a vocabulary), and workflow (how things get done). An informatist is interested in the theoretical representation, semantic interoperability, and extensive modeling of the acts and actors of healthcare.
Why was HL7 created?
Before HL7 V2, every interface between systems was custom designed and required programming on the part of both the sending and receiving application vendors.
Interfaces were expensive because there was no standard collection of patient attributes or standard set of “interesting events.”As shown in Figure 2, in the 1980s, the number of clinical interfaces in a typical hospital was small, and the cost per interface was very high. See Figure 2. in full PDF Report
The primary reason for the challenge of interfacing is that as internal hospital teams or software vendors create new clinical applications, each application is developed without input or collaboration with other application development teams. That is, rarely do commercial development teams share proprietary data on how their applications are built, so it is difficult for other teams to build compatible applications.
Some forward-thinking, like-minded, healthcare community members formed a volunteer group to make interfacing “easier” – HL7 was born. It is critical to recognize that HL7 V2 was initially created by clinical interface specialists while V3 has been mostly created by medical informatists. Consequently, the initial use and focus for each standard is keenly different.
________________________________________________________________________
To download a complete version of The HL7 Evolution, follow the PDF link below.
| Attachment | Size |
|---|---|
| HL7-Version-3-with-HL7-Version-2-History.pdf | 160.6 KB |
