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Welsh Clinical Coding Standards and Guidance


High quality data relies upon the use of agreed data standards to ensure that we are all “speaking the same language”. Use of ICD-10 5th edition and OPCS-4 is guided on a UK level by NHS England. They produce guidance in a number of forms which are applicable within Wales, including:


  • National Clinical Coding Standards Reference Books for both ICD10 and OPCS-4, available through the through the NHS England Technology Reference data Update Distribution (TRUD) website. These contain the current data standards for the application of classification codes to admitted patient care episodes.

  • The Coding Clinic, a regularly updated electronic record containing current clinical coding national standards and guidance, errata, best coding practice, educational and technical theory, and practical examples of clinical coding.

  • Training materials used on courses organised and provided by DHCW. These are provided by NHS England, and taught by approved trainers to reflect current information standards.

  • Responses to the Clinical Classifications Service.


More information about NHS England’s information standards and guidance can be found on their website. In addition to the above UK standards, Welsh Clinical Coding guidance and standards exist for ICD-10 and OPCS-4 classifications, to reflect the specific requirements of the Welsh service. These standards are produced and maintained by Digital Health and Care Wales (DHCW). These include:


Welsh Clinical Coding Standards
Clinical Coding Standards specify which information must be captured, and how it should be recorded. Clinical Coding Change Notices (CCCNs) were introduced in 2009 and are used to communicate a new or changed standard to the service. CCCNs are approved by the Welsh Information Standards Board (WISB) and published by the DHCW Clinical Classifications Team. 

Welsh Clinical Coding Guidance
Clinical Coding Communications (CCCs) are used to clarify existing clinical coding standards, and to provide guidance on how they should be applied. CCC's are approved by the Welsh Government Head of Information Standards' Clinical Coding Advisory Group (CCAG), and published by the DHCW Clinical Classifications Team. 

Local Policies
Where long term or recurrent clinical or documentation issues affect the correct assignment of a code to represent an operation or diagnosis, a local policy can be developed to provide clarity. Local policies are not intended to replace UK or Welsh Standards, and as such, they cannot contravene pre-existing data collection requirements. The process for developing and maintaining Local Policies varies by organisation, but they are approved by the DHCW Classifications Team. 

NHS Wales Data Dictionary
The standards which govern the use of Classifications data are underpinned by the data sets in which they are collected, and the definitions specified in the NHS Wales Data Dictionary. Data Set Change Notices (DSCNs) and Data Dictionary Change Notices (DDCNs) are approved by the Welsh Information Standards Board (WISB) and published by the DHCW Data Standards Team. Details of current definitions can be found in the NHS Wales Data Dictionary; details of how UK level definitions interact with Welsh data reporting for coding purposes can be found in WCG14: Interpretation of NHS England Data Definitions for the Purposes of Clinical Classification Coding.