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Thesaurus of Medical Terms

The Thesaurus of Medical Terms, under development from, is a universal clinical coding solution designed to eliminate errors and data interoperability problems in medical coding terminologies.

"The primary purpose of clinical coding is improve health care delivery to patients."

Dr Roger Weeks, GP and Clinical coding specialist

The Thesaurus of Medical Terms:

  • Corrects terminology hierarchies
  • Corrects inter-terminology maps
  • Removes duplicates
  • Enables seamless data exchange between coding terminologies
  • Updates electronic health records from Read v2.0 & v3.0 to Snomed CT

National Information Board - November 2014

The following extract from the NIB framework emphasises the governments objective to substitute the current Read code terms in electronic health records for SNOMED CT.

"The NIB endorses the move to adopt a single clinical terminology – SNOMED CT – to support direct management of care, and will actively collaborate to ensure that all primary care systems adopt SNOMED CT by the end of December 2016; the entire health system should adopt SNOMED CT by April 2020. During this time, we must also work with local authorities to understand and address the implications of this for social care."

The switch from Read to Snomed CT - critical issues

From 2016 GPs in the England will be required to use a different coding system to record and display patient information such as diagnoses and treatments. The current coding system, Read Codes, has been in use for over 20 years. The new system, SNOMED CT, is untried in electronic health records (EHRs) and in its current state could change information in EHRs and compromise patient safety, disrupt clinical practice, commissioning and research. The Thesaurus of Medical Terms eliminates these problems in legacy data and provides a terminology agnostic solution to updating EHRs.

Read to Snomed CT - the critical transition

When Read codes are replaced by SNOMED CT the two terminologies need to be accurately mapped to each other so that equivalent terms are stored and displayed. Our analysis shows that many of the codes are mapped inaccurately or there is a lack of equivalence. Left uncorrected this will lead to an unknown number of errors to be introduced into patient records.

Thesaurus of Medical Terms

The Thesaurus of Medical Terms from corrects existing clinical coding hierarchies and enables complete data interoperability between different clinical terminologies. Explore the applications for the Thesaurus of Medical Terms... more


Issues with Clinical Coding

We have spent in excess of five years analysing the Read and SNOMED CT codes and their mapping. Our analysis shows a significant number of errors within each terminology and between the two. The data has been evaluated by a skilled coding expert and the problems are expressed in a number of categories such as duplications, incorrect mappings, terms in the wrong place, missing terms ...more


Impact and consequences of clinical coding transition

The most immediate impact upon switching from Read codes to SNOMED CT will be that information in patient records will change automatically with no indication to the doctor. In an age where most patients do not have a "family" GP, it is unlikely that GPs will be able to identify errors readily...more