Object Orientation: A Natural Evolution for HL7

Object-oriented technology is having a significant impact on the analysis and programming techniques used in information systems. The same concepts are also providing the basis for standardizing interfaces among applications and components thereof. These specifications exist at both the conceptual level and in terms of the detailed level of specificity needed for "plug and play" cooperation. These specifications not only apply to functions developed using object-oriented tools, but also provide a convenient model for interfacing legacy applications. There is significant interest in providing a set of standards for exchanging healthcare data and invoking healthcare functionality using object-oriented approaches. Some probable requirements for these interfaces are described in this paper including exchanging data by query and update notification and interfacing with compound documents and other componentized functions. There are a number of competing specifications for object-oriented interfacing in the information system industry. A specific mapping is proposed from HL7 Version 2.2 to an abstract object model based on healthcare application objects and healthcare data objects. This abstract model would be independent of any specific specifications, and a significant part of any complete specification for any of them. It is further proposed that HL7 support special interest groups to develop implementation guides describing how to apply the abstract object model to any of the specific, detailed approaches.