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According to a study made in 2005, “every year at least 98,000 Americans die and millions more are injured as a result of medical errors” [1]. This is the situation of a developed country. The situation of developing countries like Pakistan is even worse, but we never know exact human losses. The experts proposed solution to this problem is to bring standards into the health-information exchange. According to another study, “standardized information exchange would save the US nation $86.8 Billion each year”. It was the motivating factor for some volunteers in US to lay foundation for an organization namely Health Level Seven (HL7). HL7 is an international, well-reputed and leading standard that facilitate the healthcare domain in providing interoperability for exchanging health-related information.

HL7 standard first appeared in version 2.x series. HL7 version 2 is a major breakthrough and market success. More than 93% hospitals in US are using this standard [2]. With all these realities, HL7 version 2 involves a number of issues. Negotiations are required from involving parties before implementing HL7 version 2. Terminologies and concepts are specific to US paradigm. HL7 version evolution is provided in figure 1.

HL7 version evolution
Figure 1. HL7 version evolution

HL7 version 3 has been released with entirely different philosophy than that of version 2. It is indeed, a paradigm shift than mere a version shift. Its core concepts are; truly new version, futuristic version, consistent version and Internationalization. HL7 current version 3 is more appealing to accommodate the future needs in a consistent manner. We are aimed to give practical shape to the philosophy of HL7 version 3. This practice will serve the community across the borders of single region or nation. Despite the advantages of HL7 version 3, it has some challenges as well. Firstly, it is not compatible with version 2, which makes it difficult for the organizations that have been using version 2 to invest in this new version. Secondly, it is complex. It is believed that the true concepts are limited to a few heads around the world. The difference between the V2 & V3 is provided in figure 2.

HL7 V2 & V3 comparison
Figure 2. HL7 V2 & V3 comparison

Computerized Healthcare Information Systems (HIS) have been developed to process and manage data within the boundaries of an organization, hospital, or clinical laboratory. But that is not the end. World is becoming a global village where every industry (including healthcare) needs to make their information systems interoperable with each other in order to exchange and share the data.

According to conceptual framework devised [3], the sharing of information among healthcare entities and functional taxonomy has four levels;

  • Level 1: Non-electronic data – no use of IT (examples: telephone and mail).
  • Level 2: Machine-transportable data – transmission of non-standardized information via basic IT (examples: fax, PC-based scanned documents, PDF files etc.).
  • Level 3: Machine-organizable data – transmission of structured messages containing non-standardized data (examples: email with free text, PC-based exchange of incompatible format, HL7 version 2 messages).
  • Level 4: Machine-interoperable data – transmission of structured messages containing standard and coded data (examples: automated exchange of coded results from an external lab into a provider’s EMR, automated exchange of patient’s “problem list”, HL7 version 3 messages)

Four levels of information sharing
Figure 3. Four levels of information sharing

Taking an example of laboratory tests, the cost of handling papers and phone calls associated with test. The proportion of tests (and costs) that are redundant Healthcare Information Exchange and Interoperability reduces costs pertains not only the mentioned areas but also the administrative portion of tests. Interoperability between these organizations would enable computer-assisted reduction of redundant tests, and it would reduce delays and costs associated with paper-based ordering and reporting of results.
According to some facts and figures [3], these savings would produce an annual national benefit of $8.09 billion at level 2, $18.8 billion at level 3, and $31.8 billion at level 4. Moreover, provide-laboratory connectivity provide  the clinicians better access to patient’s longitudinal test results, eliminate errors associated with reporting results orally, optimize ordering patterns by making on information on test costs readily available to clinicians, and make testing more convenient for patients.

Although other standards are existed but the graph of HL7 is higher than all. A survey conducted by Healthcare Information and Management Systems Society (HIMSS) providese the percentage of usage of these standards as shown in figure 4.

Four levels of information sharing
Figure 4. Usage of different standards among healthcare providers

HLH Project

NUST School of Electrical Engineering and Computer Science (SEECS) is a center of excellence. It has a vision and interest in research and development projects having measurable social aspects. In simple words, SEECS prefer those projects which can create real product. No one can ignore the importance of pure research but responding to the ground realities; we need applied research more than pure research. HLH (Health Life Horizon) is a kind of applied research project. The descriptive title of this project is; Design and Implementation of HL7 Version 3 Open Source Application for e-Health Services. It is initiated in year 2008 and is fully funded by National ICT R&D Fund, Pakitan. The purpose is to bring hospitals and clinical laboratories at the level where they can share healthcare data with any other hospital/laboratory of the world.

HLH project has several modules which will be developed in several phases within three years. Different modules are depicted in Figure 5.

Health Life Horizon Project Modules
Figure 5. Health Life Horizon Project Modules

System Architecture

In the context of healthcare messaging, HL7 standard is concerned with data contents exchanges between healthcare applications, sequence, or interrelationship in the flow of messages and the communication of significant level of exception or error conditions. So the HL7 compliant HIS will perform core functionalities autonomously and independently from HL7 core component. HIS will only interact with HL7 interface when the system exchanges data with other sub systems, external HIS or service. Within established HIS network, each HIS HL7 interface implements all necessary application roles – having defined messages. Figure 1 shows the HL7 compliant HIS network.The application we plan to develop will act as HL7 studio, which will support GUI based message specification tools, HL7 V2 to V3 conversion platform, database mapping tools, application roles deployment tools, web service deployment tool and ontology integrator tool. The architecture of the application is depicted in figure 6.
Health Life Horizon Project Architecture
Figure 6. Health Life Horizon Project Architecture

A. GUI (Graphical User Interface)
The application will support rich functionality of drag and drop while specifying message specification. It will also provide easy to use GUI for V2 and V3 mapping and database mapping. This component will also provide different wizards to deploy HL7 application roles and integration facility with existing healthcare information systems. The GUI is based on Model View Controller architecture.

B. HL7 Studio Core Engine
This component consists of subsystems to provide different functionality. For example, V2 to V3 mapping tool allows the conversion of HL7 V2 and HL7 V3 messages. Similarly, over all message management is handled by HL7 message management tool, while the generation and parsing responsibility is assigned to HL7 message generator and parser tool. The generator and parser tool use HL7 Java SIG API for message generation and parsing. Another important flavor of the application is the capability of deploying application having specific responsibilities required for particular organization. All these responsibilities are related to application roles, which are handled by Application Role Deployment Component. It takes information from specification generated by Message Management Component and deploys the application with the specified application roles and specified transportation wrapper using Transportation Component.

C. HL7 Database Mapper
HL7 specification does not provide any guidelines for mapping of HL7 messages to database schema, but database mapping is considered as one of the most important component of any HL7 implementation. The HL7 database mapper component provides the mapping of HL7 messages to database schema. The mapping will be achieved using intermediary mapping specification files and hibernate technology of object to relation mapping. The tool will provide visual mapping capabilities and will generate corresponding mapping code for specified HL7 messages.

D. HL7 Ontology Engine
In current version of HL7 V 3.0, the vocabulary domain (i.e. concepts representing all coded attribute values) has been aligned in different concept tables that present the view of semantic interoperability. But, this is semantic without ontology. Our aim is to develop ontologies for these concepts and then build ontology inference engine that can resolve different concepts for these attributes in a cohesive manner. This component will act as our proposed ontology engine. The main intention is to develop ontology for each message type in HL7 standard and the system then consumes those ontologies to generate and parse HL7 messages.

E. HL7 Transportation Component
HL7 has specified the message transportation using three different mechanism; MLLP, ebXML and Web Service. The Transportation Component helps in providing options for using different wrappers to the message transfer. The selection of one of these transportation mechanisms depends on the business model and type of applications on source and destination sides.

HLH Objectives, Outputs abd Benefits

HLH is a comprehensive project. It has several flavors to consider for its successful completion. It is an applied research project. Industry cooperation, for implementing the system in real scenario, is at the heart of this concept. Our purpose is to provide a maintainable and flexible open source software system that can be localized and customized within HL7 framework for heterogeneous requirements of various countries. 

A. Objectives

  • To provide the world with cost-effective, easily accessible open source HL7 version 3 solution that can be used in real environment. 
  • To provide the healthcare organizations and hospitals that have been using HL7 version 2 with the facility of HL7 version 3 conversion.
  • To help the healthcare organizations and hospitals of different countries customize this solution to their specific requirements with minimum efforts.
  • To create experts community in the domain of healthcare information exchange and interoperability for the purpose of taking initiative for affiliation of Pakistan to HL7 organization.
  • To research for transforming the architecture into novel ontology-based system architecture.

B.  Outputs
As our project is a phase-based project, its outputs can be realized in various releases.

  • In first release, we will make available open source system components for two domains; Laboratory and Patient Administration.
  • In second release, we will complete HL7 Version 2.x to Version 3 convertor component.
  • In third release, we will extend the system to other domains like Accounting and Billing, Scheduling, Medical Records and many others.
  • In fourth release, we will complete deploying prototype model of semantic based HL7.
  • In fifth release, we will develop the proposed architecture for SOA based HL7.

C.  Benefits
HLH project will result in plug & play system and can be integrated to the health information systems already in use. It will be usable equally by all small as well as large organizations. Different healthcare organizations either locally or globally can be benefited from our system as it is open source.

The easiest customers to be attracted to our system are among those organizations that have been already running HL7 version 2. They are interested in a system that supports not only version 3 but also conversion from version 2 to version 3. Our system is first choice to select from the public domain. One such example is North Shore Medical Labs (NSML), USA. NSML is using HL7 version 2 and can install our system without extra investment.
Locally, different organizations can use this system with little customizations. For example; CITI Lab, Pakistan is a renowned clinical laboratory having several branches and collection points at different cities in Pakistan. It has laboratory information system at each branch/collection point to manage and process patient tests data but has a great problem of transferring patient tests’ orders and tests’ results data from one branch/collection point to another branch/collection point. Currently, they are using mailing service for collecting tests orders and specimens and phone call for dictating tests results. Our system is an ideal choice for CITI Lab to overcome issues associated with phone calls and mailing services. As a ground work, we have collected their requirements.

Future is of ontologies. There is no system in hand that provides HL7 ontology. We have very strong research potentials in our university in ontology arena which will enable us to develop architecture for ontology-based HL7. The research centers all over the world can select this system to further enhance research in this area.

Today many of the organizations are interested to use SOA for their business as SOA provides best business model and is aligned with current technology trends. The healthcare organizations that are interested in SOA will be in need of a system that provides standards (HL7) with SOA which we are going to provide.

In a nutshell, our system will provide  the clinicians better access to patient’s longitudinal test results, eliminate errors associated with reporting results orally, optimize ordering patterns by making on information on test costs readily available to clinicians, and make testing more convenient for patients.


  1. Kohn LT, Corrigan JM, Donaldson MS, eds, “To Err is Human: Building a Safer Health System”, Washington, DC: National Academy Press; 1999.
  2. Nadeem G. Chaudry, Saira Ilyas, Asif Shahzad, “An Open Source Health Care Management System for Pakistan”, Paper ID- ICOST2006-10, 2006.
  3. Walker, Eric Pan, Douglas Johnston, Julia Adler-Milstein, David W. Bates, and Blackford Middleton, “The value of Health Care Information Exchange and Interoperability”.

Principal Investigator
Funding Agency
HL7 Organization
10th International HL7 Interoperability Conference 2009
Healthcare Information and Management Systems Society (HIMSS)