The increasing demands on medical terminologies

Traditional schemes cope well when used appropriately. However in recent years there has been a proliferation in the uses for systematically recorded medical information and medical terminologies. For example computer-based medical information systems, medical knowledge-based systems, and bibliographic systems all make use of medical terminologies. This increase in the demands on terminologies has resulted in a qualitative change in the requirements placed on the various coding and classification schemes. In particular there is now a need to support:

• large numbers of complex detailed descriptions e.g. clinical descriptions in medical records
• multiple uses for information e.g. patient care, quality assurance, medical audit, health services management, literature retrieval, decision support
• automatic manipulation by large computer-based information systems
• multi-lingual and multicultural use.
• frequent extensions for local use and variations

These requirements are the reverse of the original assumptions that form the justification for the use of traditional classifications. The first response to these new requirements has been to extend the content and structure of traditional schemes. Several of the major schemes have increased in size and complexity by one or more orders of magnitude. Various additional mechanisms are being proposed and adopted such as modifiers and the grouping of codes. However fundamental problems have arisen with all such schemes that limit their ability to cope with new demands.