Coding & Terminology Systems

Clinical and health related data are collected on various national patient based datasets (e.g. Scottish Morbity Records, Scottish Cancer Registry). To ensure data is recorded consistently and accurately, nationally agreed coding systems are used. These coding systems are the International Classification of Diseases, Tenth Revision (ICD-10) for diagnoses and the Office of Population Censuses and Surveys, Fourth Revision (OPCS4) for procedures and interventions and Read codes in primary care. SNOMED-CT will eventually become the terminology of choice and will cover both primary and secondary care encompassing all the coding systems mentioned above and allow the NHS in Scotland to progress towards an electronic patient record.

ICD-10

The International Statistical Classification of Diseases and Related Health Problems (ICD) is a detailed index of diseases and injuries that is developed and released by the World Health Organisation  (WHO). In Scotland information about a patient's diagnosis is recorded in their notes by the clinician treating them and then translated into ICD-10 codes by a clinical coder. It is possible to select and compare conditions consistently, not only in Scotland but also across the world wherever ICD-10 is used. This information is used for not only epidemiological purposes but also for health service planning and clinical audit at both a national and local level.

ICD is revised periodically and is currently in its tenth edition. ICD-10 was developed in 1992 to track morbidity statistics and Scotland adopted its use in 1995. Since its launch there have been 2 major updates and minor annual updates which are published by WHO.

Help and information on ICD-10 is available from the Terminology Advisory Service helpdesk on 0131 275 7283.

OPCS

The Office of Population Censuses and Surveys' Classification of Surgical Operations version 4 (OPCS4) was first issued in September 1987 to record operations and procedures carried out in the acute sector although coding of surgical procedures had been ongoing since 1944. It is now in its fourth revision with the latest release, OPCS4.3, implemented in April 2006 and was expanded to include interventions. In Scotland OPCS codes are used in SMR returns to record operations, procedures and interventions.

Connecting for Health  co-ordinate the update of OPCS in the UK and have announced (September 2007) that there will be no OPCS4 update in 2008. It is likely to be reviewed next year with possibly another implementation in 2009.

Help and information on OPCS Codes is available from the Terminology Advisory Service helpdesk on 0131 275 7283 or via email .

Read Codes

Read codes originated as a thesaurus designed specifically to enable general practitioners to code and record all relevant information arising from a patient encounter. Read codes have become widely used in general practice and primary care. The Read codes enable a summary of the medical record to be coded and stored in a computer system and contain mapping fields/tables which can provide IDC10 (International Statistical Classification of Diseases and Health Related Problems, Tenth Revision) and OPCS4 (Office of Population Censuses and Surveys, Fourth Revision) codes required for the national information returns such as Scottish Morbidity Records.

Read codes are updated twice yearly, in April and October and code requests in Scotland are co-ordinated by the Terminology Service. Details of the latest changes, April 2007, are available to download . Connecting for Health have announced (September 2007) that  updates of the Read codes on CD will be discontinued after the April 2008 release. All future updates can be downloaded by registering on the TRUD website. 

Help and information on Read Codes is available from the Terminology Advisory Service helpdesk on 0131 275 7283 or via email .

SNOMED-CT

The Systematised Nomenclature of Medicine - Clinical Terms, SNOMED-CT, is a result of a collaboration between the College of American Pathologists and the NHS in the UK.  In January 2002 SNOMED CT® was created by the merger, expansion and restructuring of SNOMED RT ® (Reference Terminology) and the UK NHS Clinical Terms Version 3 (also known as the Read Codes). The historical strength of SNOMED RT was its terminologies for speciality medicine, while the strength of Clinical Terms Version 3 was its terminologies for Gerneral Practice. By combining these two systems, SNOMED CT is the most comprehensive clinical vocabulary available covering most aspects of clinical medicince with over 414,000 concepts covering diseases, clinical findings and procedures. It also allows a consistent way to index, store, retrieve and aggregate clinical data across specialities and sites of care. It also helps structure and computerise the medical record, reducing the variability in the way data is captured, encoded and used for clinical care of patients and research. SNOMED created a common clinical language that is a necessary element of a health care information infrastructure.

SNOMED content is updated twice a year in the UK in April and October and the Terminology Service co-ordinate code requests from users in Scotland.

Help and information on SNOMED is available from the Terminology Advisory Service helpdesk on 0131 275 7283 or via email .