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Standards for health care telematics - A new dimension and challenge to standards makersBy Sigurd FromIntroductionThe implementation of telemedicine applications on a large scale requires standards for the exchange of health care information to be in place. Norwegian Telecom participates in several standardisation projects both internationally and nationally, which develop standards for electronic exchange of health care information. This paper presents the work related to CEN/TC 251, the European initiative for establishing standards in health care informatics and telematics. The objective of this paper is to introduce a method for structuring health care telematics standards.StandardisationThe traditional motivation for developing standardsThe development of standards has traditionally played an important role in the spread of technology in Western society. In the highly specialised industry, products are assembled into new more complex products. A producer of a product may require many suppliers for the component products. Each component must have a well defined functionality. In order to achieve an acceptable price for the component, the same component should be usable in many products. The many-to-many relationship between producers and suppliers requires open specification - standards - to be handled efficiently. This is illustrated in figure 1.ISO's definition of a standardIn order to establish a standard, the interested parties come together and form standard committees. ISO - the International Standardisation Organisation - is the largest standard making body in the world and holds a number of technical committees which develop international standards in many fields. ISO defines a standard to be:Document established by consensus and approved by a recognised body, that provides, for common and repeated use, rules, guidelines or characteristics for activities or their results aimed at the achievement of a maximum degree in a given context. Standards should be based on the consolidated results of science, technology and experience, and aimed at the promotion of optimum community benefits. In practice, standards are documents that are used to set requirements to products so that the buyer has a guarantee for the quality of the product. To verify that a product conforms to standards, third party test laboratories, which certificate the products, have been set up. In later years, the EC and EFTA countries have, as a result of preparing the common European market, increased the standardisation and harmonisation activity. Standards are used instead of governmental regulations. The standardisation process within the European standardisation bodies, CEN, CENELEC and ETSI, is open for participation from all interested parties in Europe. Experts in all fields are encouraged to participate. The final formal votes are made by delegates from the national standardisation institutes. Health care telematics standardsThe need for standards in health care telematicsAs indicated both in other papers in this journal (From, 1993) and elsewhere (De Moor, 1993) a number of telemedicine and other health care telematics applications are under development.Health care telematics applications require electronic exchange of information between computer systems. In order to fulfil this requirement, the systems need to share health care concepts. Only those concepts which are supported by both the sending and receiving system can be interpreted correctly and result in meaningful information exchange. This is illustrated in figure 2. Information exchanged between systems must be represented technically in such a way that it can be transported across electronic networks. Today, a number of health care applications emerge, using their own interchange formats for health care messages. This makes it difficult and expensive to integrate systems from different vendors. Standards in health care telematics are needed to define both the health care requirements such as the health care concepts, and the technical solutions such as interchange formats. Categories of standardsHealth care telematics can be described along two dimensions:
It may be useful to distinguish between different types of standards depending on whether their primary focus are health care or technology. For the remainder of this paper four categories of standards will be used:
The health care standards (HC-standards) describe common health care needs. Today, manual paper forms for information exchange are created locally without co-ordination with other health care organisations. The lack of co-ordination results in a diversity in the use of terminology for health care concepts. This diversity becomes a problem when the paper forms are substituted by electronic communication systems. Common health care requirements are needed to allow for information exchange between heterogeneous systems and to reduce production and maintenance cost of the systems. This category covers standards such as Health Care Domain Descriptions (HCDDs), Communication Scenario Descriptions (CSDs), Coding systems, and Security Requirements. The second category is the Information Technology Standards (IT-standards). This category includes standards for open systems interconnections (OSI), system architectures, user interfaces, storage, etc., which are independent of health care. In order to realise a health care telematics application, HC-standards and IT-standards must be combined in an implementation. As shown in figure 4, Implementation standards (Im-standards) for health care telematics applications are created by mapping HC-standards onto IT-standards. This mapping process is guided by special mapping standards defined in category 4. IM-standards cover Interchange Format Dependent Message Descriptions (IFDMDs), Functional Profiles of OSI-standards for use in health care, and different types of Implementation Guidelines. The Supporting and Methodological Standards (SM-standards) are technological standards developed specifically to support the establishment of health care telematics standards. They are not themselves used in a health care telematics applications. This category includes methods for developing HCDDs and CSDs and a metamodel for coding systems. In addition supporting standards such as registration procedure for coding systems and medical informatics vocabulary are included. CEN TC/251 on standards in health care informaticsThe European Committee for Standardisation (CEN) established in 1990 a technical committee for health care informatics, CEN/TC 251. The objectives of CEN/TC 251 are the organisation, the co-ordination and the follow-up of standards development, including testing standards in health care informatics and telematics at a European level (12 EC-countries, 7 EFTA-countries, 7 Eastern European countries). The development of such standards requires people with both medical and technical skills.The final standards from CEN/TC 251 are aimed for use in the health care sector. CEN/TC 251 therefore only develops HC-standards, Im-standards and SM-standards. IT-standards are imported from other standards groups such as ISO/IEC JTC1, CCITT, ETSI, and EWOS. CEN/TC 251 has defined a work programme (CEN, 1993). The work is divided into 7 working groups: WG 1 Health Care Information Modelling and Medical Records WG 2 Health Care Terminology, Semantics and Knowledge Bases WG 3 Health Care Communications and Messages WG 4 Medical Imaging and Multimedia WG 5 Medical Devices (communication with) WG 6 Health Care Security and Privacy, Quality and Safety WG 7 Intermittently Connected Devices (incl. patient-data-cards). Each working group supervises a number of Project Teams (PTs). The work in a PT is undertaken by especially assigned experts and is funded. Until April 1993 the following PTs have been established:
Project Moni- Description
Team toring
WG
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PT 001 WG 1 Medical informatics vocabulary
PT 002 WG 2 Terminology and coding systems of medical procedures
PT 003 WG 2 Model for representation of semantics
PT 004 WG 3 Investigation of syntaxes for existing Interchange Formats
to be used in health care
PT 005 WG 3 Procedures for registration of coding systems related to
health care
PT 006 WG 4 Medical image and related data information format standards
PT 007 WG 5 Standard interchange format and communication protocol for
computerised electrocardiography
PT 008 WG 3 Messages for exchange of laboratory information
PT 009 WG 7 Identification, administrative and common clinical data
content for intermittently connected devices used in health care
PT 010 WG 1 Health care information framework
PT 011 WG 1 Electronic health care records architecture
PT 012 WG 6 Security for health care information systems
PT 024 WG 3 Functional profiles for medical image interchange.
(ewos)
In addition to WGs and PTs, CEN/TC 251 has close liaisons with many other European and
International organisations. Two of these are the EWOS/EG MED (European Workshop on
Open Systems, Expert Group Medical) which handles functional profiles of OSI for use in health
care, and the WEEB MD9 (Western European EDIFACT Board, Message Development Group
for Health Care) which develops EDIFACT messages for health care which fall in the category of
Im-standards.
Health care standardsHC-standards describe solutions to common needs in a health care sector. HC-standards should be the result of a consensus process involving health care experts.Health care domainsThe health care sector may be separated into health care domains. CEN/TC 251 is addressing a number of domain in its work programme. Figure 5 indicates the health care domains currently under study and put them into a hierarchical structure to show their dependencies. The most general domain is found at the top; the most specific domains at the bottom.The figure shows that clinical laboratory medicine is a sub-domain of the diagnostic services domain which means that clinical laboratory medicine is a specialisation of diagnostic services. Similarly, the diagnostic service domain is a sub-domain of health care in general. The figure only shows the specialisation-generalisation structure between the domains. Other relationships also exist but are not discussed here. Categories of health care standardsEach health care domain has different properties which are described by different types of standards. We have chosen to categorise the health care standards into four groups as shown in figure 6.Health care domain descriptions (HCDDs)For each health care domain addressed, the user requirements need to be formally documented. The Health Care Domain Description (HCDD) defines the concepts used in a domain. As an example for the laboratory medicine domain, concepts such as laboratory service order, patient, investigation requested, are defined in the HCDD. In addition to the concept definitions, the HCDD includes a Domain Information Model (DIM) which defines the relationships between each concept in the domain. Figure 7 shows an example of a list of concepts and a DIM.Communication scenario descriptions (CSDs)In Open-Edi, a scenario is defined as a formal description of a class of business activities (Open-Edi, 1991). In health care the Communication Scenario Descriptions (CSDs) are used to describe information exchange between communication parties. A communication party is a health care person or organisation which participate in the communication. Each communication party has one or more communication role which defines their behaviour in a communication situation. For instance, a doctor requesting a laboratory analysis is a requester. It is the role as requester that is important in a laboratory requesting situation. Similarly the laboratory is the provider. Communication roles may be held by different communication parties. In the example, the doctor as a requester may be substituted by a nurse or a veterinarian who issues a laboratory request.A set of services are associated with each communication role. A service defines a specific behaviour that the party holding the role is responsible for exhibiting when the service is requested. The CSD shows the logical messages exchanged between the communication roles. A simplified communication scenario taken from the Laboratory Medicine Domain is shown in figure 8. A logical message incorporates a selected amount of information which is exchanged between two systems for a given purpose e.g. a request for a service or a report from a performed service. The General Message Descriptions (GMDs) are defined as the result of combining a HCDD with a CSD. This is shown in figure 9. For each logical message in the CSD a view of the Domain Information Model (DIM) in the HCDD is created. This becomes the GMD. One HCDD may relate to many CSDs. Similarly, one CSD may relate to many HCDDs. For each instance of the relationship between HCDDs and CSDs, one or more GMDs are created. A GMD resulting in the combination of the logical message "New Laboratory Service Order" in the scenario above and the DIM described in figure 7 is shown in figure 10. Concepts and coding systemsMost health care information processing requires the use of medical coding systems. Coding systems are often domain dependent. The preference for coding systems varies between the users and there is often more than one system used in a domain. We have chosen to handle coding systems as a separate type of health care standards.Security requirementsSecurity is an important aspect which influences almost all areas of health care telematics. Security includes issues such as confidentiality, integrity and availability. It is important to clarify and harmonise the security requirements for each health care domain and for health care in general.Relationship to CEN/TC 251's Work ProgrammeThe development of HC-standards are undertaken by the different WGs in CEN/TC 251. Each WG has been assigned a number of work items described in the CEN/TC 251 Work Program. Table 1 shows the relationship between HC domains, WGs and work items. For each work item the type of HC-standard is indicated by the colour of the intersection.Work item 1.6: The health care record is an extended version of the medical record which covers all types of health care information related to a patient. The objective of this work item is to define an overall architecture for the health care record and the various components of it. Information technology standardsCEN/TC 251's objective is to develop standards in the field of health care informatics and telematics. It is not the intention to develop new standards for new technology. Technology standards, and particular IT-standards, have their origin in bodies such as ISO/IEC JTC 1, CCITT, ETSI and EWOS. CEN/TC 251 should import IT-standards from these international and European bodies. The number of IT-standards is large. The categories most relevant to health care telematics applications are:
Standards for bar-codes is an example of another type of technological standard that may be required in e.g. communication between general practitioners and laboratories in order to identify samples unambiguously. Implementation standards of health care telematicsIm-standards are created by mapping HC-standards onto IT-standards guided by special mapping rules. Figure 12 shows three categories of Im-standards: Interchange Format Depended Message Descriptions (IFDMD), Functional Profiles of OSI, and Implementation Guidelines.Interchange format depended message descriptionsIFDMDs are created by mapping GMDs to a selected Interchange Format (IF). One GMD may be mapped to different IFDMD using different IFs. This is shown in figure 13.The first step in a mapping should be to select the IF to use. The requirements to information structure and data types given by the GMD and the different IFs' ability to meet these requirements, should determine which IF is selected. PT 004 has developed a method for selecting interchange formats based on GMD requirements which fall into the category of SM-standards. The second step is the actual mapping where objects and attributes in the GMD is mapped to the data elements of the IFDMD. The rules for this mapping will depend on the IF selected. PT 008 has as a part of the work of mapping GMDs to EDIFACT messages defined a preliminary method for this mapping. Functional profilesFunctional profiles are needed to ensure communication between open systems. Many options exist in the OSI base standards, which have to be resolved before real interoperability can be achieved. This is the objective of Functional Profiles. A Functional Profile may include one or more OSI base standards. Examples of Functional Profiles are found in the national OSI profiles, e.g. GOSIP and NOSIP.Most of the health care telematics applications should use existing Functional Profiles defined elsewhere. However, some applications will require special profiles. One such area is medical imaging, where large amounts of data need to be transferred fast across the network. EWOS EG MED has defined a method whereby "real world" user requirements for communication between health care systems can be mapped on to open systems profiles. The method may be used both to select existing OSI Functional Profiles and to indicate where there are needs for developing new Functional Profiles (EWOS, 1992). Implementation guidelinesThe functional requirements to health care telematics applications may vary from country to country. Still, there may be a need to ensure standard solutions within a country. Implementation Guidelines may be used to add additional implementation requirements.Supporting and methodological standardsA number of supporting standards are required to establish the HC-standards and Im-standards. Figure 14 shows those which are currently identified in CEN/TC 251.The standards are separated in three categories: Those supporting the establishment of HC-standards, those supporting mapping from HC-standards to Im-standards and a set of general supporting standards. The methods related to mapping have already been presented in chapter 6.1 and 6.2. Methods for definingHC-standardsDevelopment of HC-standards requires a standard methodology in order to ensure consistency across different HC domains. When developing health care messages, many methods and techniques may be used to describe the HC-domain and related scenarios. PT 004 (Investigation of syntaxes for existing interchange formats to be used in health care) has developed an initial method for developing HCDDs and CSDs. Object-oriented analysis is used as the description technique for DIMs and GMDs (Coad, 1991). The work is later taken over by PT 008 (Messages for exchange of laboratory information) which is trying the method in its attempt to establish messages for clinical laboratory medicine.Today's structure of coding systems is related to the manual use of the coding systems. Computers allow for a more flexible way of relating concepts and codes. A model for representation of semantics in medicine, developed by PT 003, describes a method for defining concepts and related classification and coding systems (CEN, 1993b). Standardisation supportA Medical Informatics Vocabulary is invaluable to the co-ordination of work among medical informaticians. PT 001 is undertaking the job to produce such a vocabulary.There is a need to uniquely identify existing and future coding systems to be used in health care. PT 005 is producing a standard which specifies procedures for the registration of coding systems. Results in clinical laboratory medicineClinical Laboratory Medicine (CLM) has been the HC domain which has received most attention in CEN/TC 251. It was selected as a paradigm by WG 3 for the development of electronic messages in health care. Many of the supporting and methodological standards were identified and developed in order to establish CLM messages. Figure 15 shows the standards which are related to this domain.The standards in rounded boxes are specifically related to the CLM domain. These are:
At present, the following objectives have been reached:
At first glance, the defined method may look complex because of the number of categories and individual standards which are introduced. However, the health care telematics field is rather complex, taking the two dimensions into consideration. Separation of the HC-standards from the more technical standards should reduce the barrier for health care professionals to participate in the standard making and quality control process. It is a challenge for CEN/TC 251 to present its result in such a way that it could easily be understood by the user community. Many small and well scoped standards should be better than few, large and unclear standards. This requires co-ordination and a common framework to get consistency among the standards. New medical informatics terms have been introduced in the CEN/TC 251 work. However, the concepts behind these terms have often been explored by other standardisation groups. The concept of an object-oriented information model was first introduced by MEDIX. The concept of scenarios is under development in JTC 1/WG 3 Open-Edi. The information content of the CLM domain description is collected from standards such as ASTM 1238, EUCLIDES, EMEDI, HL7 and various national laboratory specifications. The reuse of other groups concepts is important for getting broad consensus on the resulting standards. Standards are of no use if they are not implemented. The establishment of parallel implementation projects to the standardisation process where standards can be tested, is important. A special organisation, ACOSTA, has been set up on the European level to co-ordinate R & D, standardisation and industrial promotion in the field of health care telematics. Similar co-ordination is required on national levels involving the national health authorities and user-groups in implementation projects. CEN/TC 251 has made rapid progress since its establishment in 1990. Today, about 700 individual experts are active in CEN/TC 251 including national mirror groups. Two standards are in the process of formal voting. At the beginning of 1994 a complete set of standards in the CLM domain are expected. Standards in the other domains vary from 1994 to 1996 depending on whether paid project teams are used to carry out the work. CEN/TC 251 represents a new construction in the formal standardisation world. It serves a specific user-community (health care). Standardised user requirements are given to the technical standardisation bodies to influence the development of IT-standards. In the future it is likely that other industry sectors will create similar standardisation mechanisms as CEN/TC 251. Even though the resulting standards of CEN/TC 251 are not transferrable to domains outside the health care sector, the methods developed are fairly general and could easily be exported. CEN/TC 251 may then be a paradigm for a new category of user-oriented IT standardisation. ReferencesCEN. 1993a. Directory of the European standardisation requirements for health care informatics and programme for the development of standards. Gent, CEN/TC 251. (Draft version 1.7.)CEN. 1993b. Model for representation of semantics in medicine. Gent, CEN/ TC 251. (Document 1993/N 5.) CEN. 1993c. Investigation of Syntaxes for Existing Interchange Formats to be used in Health care. Gent, CEN/TC 251. (Document N93-87.) CEN. 1993d. Health care informatics interchange, Registration of coding schemes. Gent, CEN/TC 251. (Document N93-44.) CEN, 1993e. Structure for classification and coding of Laboratory Procedures, CEN/TC 251. (Document N93-3.) Coad, P and Yourdon, E. 1991 Object-Oriented Analysis. 2nd edition. Englewood Cliffs, New Jersey, Prentice Hall. ISBN-0-13-629981-4. De Moor, G. 1993. Standardisation in Health Care Informatics and Telematics in Europe: CEN TC 251 Activities. In : De Moor et al. Progress in Standardisation in Health Care Informatics. Amsterdam, ISO Press, 52-59. ISBN 90-5199-114-2. EWOS. 1993. A Method for defining functional profiles for health care. Brussels, EWOS EG MED. (Document EWOS/EG MED/92/26.) From, S, Stenvold, L. A, Danielsen, T. 1993. Telemedicine services integrated into a health care network. Telektronikk 1, 12-22. |
