title: Knowledge-based approaches to the maintenance of a large controlled medical terminology.
abstract: OBJECTIVE
  Develop a knowledge-based representation for a controlled terminology of clinical information to facilitate creation, maintenance, and use of the terminology.
  
  
  METHODS
  The Medical Entities Dictionary (MED) is a semantic network, based on the Unified Medical Language System (UMLS), with a directed acyclic graph to represent multiple hierarchies. Terms from four hospital systems (laboratory, electrocardiography, medical records coding, and pharmacy) were added as nodes in the network. Additional knowledge about terms, added as semantic links, was used to assist in integration, harmonization, and automated classification of disparate terminologies.
  
  
  RESULTS
  The MED contains 32,767 terms and is in active clinical use. Automated classification was successfully applied to terms for laboratory specimens, laboratory tests, and medications. One benefit of the approach has been the automated inclusion of medications into multiple pharmacologic and allergenic classes that were not present in the pharmacy system. Another benefit has been the reduction of maintenance efforts by 90%.
  
  
  CONCLUSIONS
  The MED is a hybrid of terminology and knowledge. It provides domain coverage, synonymy, consistency of views, explicit relationships, and multiple classification while preventing redundancy, ambiguity (homonymy) and misclassification.
authors.affiliation: Columbia University, New York, NY, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Cimino
authors.forename: P D
authors.initials: PD
authors.lastname: Clayton
authors.forename: G
authors.initials: G
authors.lastname: Hripcsak
authors.forename: S B
authors.initials: SB
authors.lastname: Johnson
mesh_terms: D003198:Computer Simulation; D012660:Semantics; D009626:Terminology as Topic; D017432:Unified Medical Language System